Add verify_ssl to OpenStack credential type

To avoid verification failures when using a self-signed certificate file,
 Added "Verify SSL" check box to the openstack credential type edit page.

Signed-off-by: Hideki Saito <saito@fgrep.org>

awx/main/models/credential/__init__.py

@@ -970,6 +970,10 @@ ManagedCredentialType(
                                        'It is only needed for Keystone v3 authentication '
                                        'URLs. Refer to Ansible Tower documentation for '
                                        'common scenarios.')
+        }, {
+            'id': 'verify_ssl',
+            'label': ugettext_noop('Verify SSL'),
+            'type': 'boolean'
         }],
         'required': ['username', 'password', 'host', 'project']
     }