Add some requirements to the plugin docstrings.

lib/ansible/plugins/inventory/aws_ec2.py

@@ -8,6 +8,9 @@ DOCUMENTATION = '''
     name: aws_ec2
     plugin_type: inventory
     short_description: ec2 inventory source
+    requirements:
+        - boto3
+        - botocore
     extends_documentation_fragment:
         - inventory_cache
         - constructed

lib/ansible/plugins/inventory/foreman.py

@@ -10,6 +10,8 @@ DOCUMENTATION = '''
     plugin_type: inventory
     short_description: foreman inventory source
     version_added: "2.6"
+    requirements:
+        - requests >= 1.1
     description:
         - Get inventory hosts from the foreman service.
         - "Uses a configuration file as an inventory source, it must end in foreman.yml or foreman.yaml and has a ``plugin: foreman`` entry."

lib/ansible/plugins/inventory/openstack.py

@@ -15,6 +15,8 @@ DOCUMENTATION = '''
       - Marco Vito Moscaritolo <marco@agavee.com>
       - Jesse Keating <jesse.keating@rackspace.com>
     short_description: OpenStack inventory source
+    requirements:
+        - openstacksdk
     description:
         - Get inventory hosts from OpenStack clouds
         - Uses openstack.(yml|yaml) YAML configuration file to configure the inventory plugin