HADOOP-11307. create-release script should run git clean first (kasha)

(cherry picked from commit 4fb96dbe3bbfd3ae88b41c816e15acee04518851)
(cherry picked from commit c8b7146e20e7951b4e69535d56b2d8685ccfa910)
diff --git a/dev-support/create-release.sh b/dev-support/create-release.sh
index 447fbdd..7a3dd70 100755
--- a/dev-support/create-release.sh
+++ b/dev-support/create-release.sh
@@ -47,6 +47,9 @@
 # Extract Hadoop version from POM
 HADOOP_VERSION=`cat pom.xml | grep "<version>" | head -1 | sed 's|^ *<version>||' | sed 's|</version>.*$||'`
 
+# Setup git
+GIT=${GIT:-git}
+
 echo
 echo "*****************************************************************"
 echo
@@ -70,6 +73,9 @@
 
 ARTIFACTS_DIR="target/artifacts"
 
+# git clean to clear any remnants from previous build
+run ${GIT} clean -xdf
+
 # mvn clean for sanity
 run ${MVN} clean
 
diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 4f07dd0..3011771 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -16,6 +16,8 @@
 
     HADOOP-11260. Patch up Jetty to disable SSLv3. (Mike Yoder via kasha)
 
+    HADOOP-11307. create-release script should run git clean first. (kasha)
+
 
 Release 2.5.1 - 2014-09-05