Bump minimal version of ansible to 2.4.0

Currently 2.4.0 is the oldest release of ansible, everything later is
EOL. Update our meta data into include this and the platforms we
currently tests with.

Change-Id: Ia49d4ff5a121cc521a65f80a3993283b407167c3
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

meta/main.yml

@@ -19,11 +19,15 @@ galaxy_info:
     and ramdisk images.
   company: Red Hat, Inc.
   license: Apache
-  min_ansible_version: 2.0
+  min_ansible_version: 2.4
   platforms:
-  - name: EL
+  - name: Fedora
     versions:
-    - 7
+    - 27
+  - name: Ubuntu
+    versions:
+    - 16.04
+    - 18.04
   categories:
-  - cloud
+  - system
 dependencies: []

requirements.txt

@@ -1 +1 @@
-ansible>=2.0.0
+ansible>=2.4.0