Update influxdb checksum (#412)

The influxdb checksum appears to have changed again (see #381)
due to re-signing the RPM. The contents of the RPM were verified
to not have changed. Both the RPM scriptlets/metadata and the CPIO
payload are identical, but the GPG signature has a newer timestamp.

To make it clear that the checksum provided is for the influxdb package
found under https://repos.influxdata.com/centos/7/x86_64/stable/,
specify the entire URL in the defaults file rather then specify only the
name and include the rest of the URL in the get_url task.
diff --git a/ansible/roles/influxdb/defaults/main.yml b/ansible/roles/influxdb/defaults/main.yml
index a7f51c6..85883dd 100644
--- a/ansible/roles/influxdb/defaults/main.yml
+++ b/ansible/roles/influxdb/defaults/main.yml
@@ -15,5 +15,5 @@
 # limitations under the License.
 #
 
-influxdb_rpm: influxdb-1.8.3.x86_64.rpm
-influxdb_checksum: "sha512:4c0557c24e5083e9d94d49cfad496f45421bb50aacf75737ca6bff36c8ef276af884c5419b5cc74e4fa1e8062e6bee18af53e3650eaa8a6ecd656346151ea87c"
+influxdb_rpm_url: https://repos.influxdata.com/centos/7/x86_64/stable/influxdb-1.8.3.x86_64.rpm
+influxdb_checksum: "sha512:60abf31c70beb8a391ded82569532a255384516da0b3c287d20065fe7047be343c50b37bbe31d5dd8df4bcb31144ef696b90e21d6739ce375b7e4fc33bae4f03"
diff --git a/ansible/roles/influxdb/tasks/main.yml b/ansible/roles/influxdb/tasks/main.yml
index 09a4664..2b31c1b 100644
--- a/ansible/roles/influxdb/tasks/main.yml
+++ b/ansible/roles/influxdb/tasks/main.yml
@@ -18,8 +18,8 @@
 - name: "download influxdb rpm"
   get_url:
   args:
-    url: https://repos.influxdata.com/centos/7/x86_64/stable/{{ influxdb_rpm }}
-    dest: /tmp/{{ influxdb_rpm }}
+    url: "{{ influxdb_rpm_url }}"
+    dest: /tmp/influxdb.rpm
     checksum: "{{ influxdb_checksum }}"
     force: no
 - name: "Import GPG key for CentOS 8.0 and later"
@@ -29,7 +29,7 @@
     state: present
   when: ansible_facts['distribution_version'] is version('8.0', '>=')
 - name: "ensure influxdb is installed"
-  yum: name=/tmp/{{ influxdb_rpm }} state=present
+  yum: name=/tmp/influxdb.rpm state=present
 - name: "configure influxdb"
   template: src=influxdb-1.8.3.conf dest=/etc/influxdb/influxdb.conf
   notify: