Fix non-matching defaults in docs (#5446)

* Allow to pass options as lookup options.

* Adjust tests.

* Fix non-matching defaults.

plugins/modules/cloud/misc/rhevm.py

@@ -54,6 +54,7 @@ options:
         description:
             - The RHEV/oVirt cluster in which you want you VM to start.
         type: str
+        default: ''
     datacenter:
         description:
             - The RHEV/oVirt datacenter in which you want you VM to start.

plugins/modules/cloud/misc/serverless.py

@@ -35,11 +35,13 @@ options:
       - The name of the serverless framework project stage to deploy to.
       - This uses the serverless framework default "dev".
     type: str
+    default: ''
   region:
     description:
       - AWS region to deploy the service to.
       - This parameter defaults to C(us-east-1).
     type: str
+    default: ''
   deploy:
     description:
       - Whether or not to deploy artifacts after building them.

plugins/modules/cloud/misc/terraform.py

@@ -105,6 +105,7 @@ options:
         resources selected here will also auto-include any dependencies.
     type: list
     elements: str
+    default: []
   lock:
     description:
       - Enable statefile locking, if you use a service that accepts locks (such