Fixed bugs identified by newer ansible-lint

- scm: git is mandatory on requirements.yml when using git urls
- role_name is needed in meta
- centos was not listed as supported platform
- galaxy_tags should be used instead of categories
- comparison to empty string should be avoided

These where found while attempting to enable functional testing using
ansible-molecule.

Change-Id: I5f8087516628e20c2539552c653d4ea5361234ec
Needed-By: https://review.opendev.org/#/c/675615/

meta/main.yml

@@ -14,6 +14,7 @@
 # limitations under the License.
 
 galaxy_info:
+  role_name: os_tempest
   author: rcbops
   description: Installation and setup of tempest
   company: Rackspace
@@ -30,10 +31,13 @@ galaxy_info:
     - name: EL
       versions:
         - 7
+    - name: CentOS
+      versions:
+        - 7
     - name: opensuse
       versions:
         - 15
-  categories:
+  galaxy_tags:
     - cloud
     - python
     - tempest

requirements.yml

@@ -1,8 +1,10 @@
 # python_venv_build ansible role
 - name: python_venv_build
+  scm: git
   src: https://opendev.org/openstack/ansible-role-python_venv_build.git
   version: master
 # ansible-config_template action plugin
 - name: config_template
+  scm: git
   src: https://opendev.org/openstack/ansible-config_template.git
   version: master

tasks/tempest_post_install.yml

@@ -151,7 +151,7 @@
   copy:
     content: |
       {% for item in tempest_test_whitelist | unique | sort %}
-      {%   if item != '' %}
+      {%   if item %}
       {{ item }}
       {%   endif %}
       {% endfor %}
@@ -165,7 +165,7 @@
   copy:
     content: |
       {% for item in tempest_test_blacklist %}
-      {% if item.test != '' %}
+      {% if item.test %}
       {{ item.test }}
       {%   endif %}
       {% endfor %}