Update to enablerepo functionality to work better with Ansible 2.7.0.

Author: geerlingguy

molecule/default/tests/test_default.py

@@ -1,7 +1,13 @@
 ---
 - name: Ensure MySQL packages are installed.
-  yum: "name={{ mysql_packages }} state=present enablerepo={{ mysql_enablerepo }}"
+  yum:
+    name: "{{ mysql_packages }}"
+    state: present
+    enablerepo: "{{ mysql_enablerepo | default(omit, true) }}"
   register: rh_mysql_install_packages
 
 - name: Ensure MySQL Python libraries are installed.
-  yum: "name=MySQL-python state=present enablerepo={{ mysql_enablerepo }}"
+  yum:
+    name: MySQL-python
+    state: present
+    enablerepo: "{{ mysql_enablerepo | default(omit, true) }}"