ARROW-12375: [Release] Remove rebase post-release scripts

We're going to release from a maintenance branch from now on, so we won't rebase neither the master branch nor the pull requests again.

Closes #10022 from kszucs/ARROW-12375

Authored-by: Krisztián Szűcs <szucs.krisztian@gmail.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>
diff --git a/dev/release/generate_force_push_script.py b/dev/release/generate_force_push_script.py
deleted file mode 100755
index b6cd760..0000000
--- a/dev/release/generate_force_push_script.py
+++ /dev/null
@@ -1,61 +0,0 @@
-#!/usr/bin/python
-##############################################################################
-# Licensed to the Apache Software Foundation (ASF) under one
-# or more contributor license agreements.  See the NOTICE file
-# distributed with this work for additional information
-# regarding copyright ownership.  The ASF licenses this file
-# to you under the Apache License, Version 2.0 (the
-# "License"); you may not use this file except in compliance
-# with the License.  You may obtain a copy of the License at
-#
-#   http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing,
-# software distributed under the License is distributed on an
-# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-# KIND, either express or implied.  See the License for the
-# specific language governing permissions and limitations
-# under the License.
-##############################################################################
-
-# This script generates a series of shell commands
-# to rebase all open pull requests off of master
-# and force push the updates.
-
-from http.client import HTTPSConnection
-import json
-from collections import defaultdict
-
-client = HTTPSConnection('api.github.com')
-client.request('GET',
-               '/repos/apache/arrow/pulls?state=open&per_page=100',
-               headers={'User-Agent': 'ApacheArrowRebaser'})
-response = client.getresponse()
-json_content = response.read()
-if response.status != 200:
-    error_msg = 'GitHub connection error:{}'.format(json_content)
-    raise Exception(error_msg)
-
-parsed_content = json.loads(json_content)
-if len(parsed_content) == 100:
-    print("# WARNING: Only the most recent 100 PRs will be processed")
-
-repos = defaultdict(list)
-for pr in parsed_content:
-    head = pr['head']
-    repos[head['repo']['full_name']].append(head['label'])
-
-for repo, labels in repos.items():
-    print('git clone git@github.com:{}.git'.format(repo))
-    print('cd arrow')
-    print('git remote add upstream https://github.com/apache/arrow.git')
-    print('git fetch --all --prune --tags --force')
-    for label in labels:
-        # Labels are in the form 'user:branch'
-        owner, branch = label.split(':')
-        print('git checkout {}'.format(branch))
-        print('(git rebase upstream/master && git push --force) || ' +
-              '(echo "Rebase failed for {}" && '.format(label) +
-              'git rebase --abort)')
-    print('cd ..')
-    print('rm -rf arrow')
diff --git a/dev/release/post-00-rebase.sh b/dev/release/post-00-rebase.sh
deleted file mode 100755
index c80ce24..0000000
--- a/dev/release/post-00-rebase.sh
+++ /dev/null
@@ -1,42 +0,0 @@
-#!/bin/bash
-#
-# Licensed to the Apache Software Foundation (ASF) under one
-# or more contributor license agreements.  See the NOTICE file
-# distributed with this work for additional information
-# regarding copyright ownership.  The ASF licenses this file
-# to you under the Apache License, Version 2.0 (the
-# "License"); you may not use this file except in compliance
-# with the License.  You may obtain a copy of the License at
-#
-#   http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing,
-# software distributed under the License is distributed on an
-# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-# KIND, either express or implied.  See the License for the
-# specific language governing permissions and limitations
-# under the License.
-#
-set -e
-set -u
-
-if [ "$#" -ne 1 ]; then
-  echo "Usage: $0 <local-release-branch>"
-  exit
-fi
-
-local_release_branch=$1
-
-echo "Fetch the latest commits"
-git fetch --all --prune
-echo "Checkout the master branch"
-git checkout master
-echo "Apply the latest commits on the master branch"
-git rebase apache/master
-echo "Apply the unpushed commits on the local release branch"
-git rebase ${local_release_branch}
-echo "Push the rebased branch to master"
-git push --force apache master
-
-echo "Success! The rebased commits are available here:"
-echo "  https://github.com/apache/arrow/commits/master"