reference instance_id in docs, fixes for calls to fail_json

cloud/vmware/vca_fw.py

@@ -42,9 +42,9 @@ options:
         - The org to login to for creating vapp, mostly set when the service_type is vdc.
       required: false
       default: None
-    service_id:
+    instance_id:
       description:
-        - The service id in a vchs environment to be used for creating the vapp
+        - The instance id in a vchs environment to be used for creating the vapp
       required: false
       default: None
     host:
@@ -242,7 +242,7 @@ def main():
     try:
         desired_rules = validate_fw_rules(fw_rules)
     except VcaError, e:
-        module.fail_json(e.message)
+        module.fail_json(msg=e.message)
 
     result = dict(changed=False)
     result['current_rules'] = current_rules

cloud/vmware/vca_nat.py

@@ -42,9 +42,9 @@ options:
         - The org to login to for creating vapp, mostly set when the service_type is vdc.
       required: false
       default: None
-    service_id:
+    instance_id:
       description:
-        - The service id in a vchs environment to be used for creating the vapp
+        - The instance id in a vchs environment to be used for creating the vapp
       required: false
       default: None
     host:
@@ -200,7 +200,7 @@ def main():
     purge_rules = module.params['purge_rules']
 
     if not purge_rules and not nat_rules:
-        module.fail_json('Must define purge_rules or nat_rules')
+        module.fail_json(msg='Must define purge_rules or nat_rules')
 
     vca = vca_login(module)
 

cloud/vmware/vca_vapp.py

@@ -104,15 +104,10 @@ options:
         - The org to login to for creating vapp, mostly set when the service_type is vdc.
       required: false
       default: None
-    service_id:
-      description:
-        - The service id in a vchs environment to be used for creating the vapp
-      required: false
-      default: None
     instance_id:
       description:
-        - The vCloud Air instance ID
-      required: no
+        - The instance id in a vchs environment to be used for creating the vapp
+      required: false
       default: None
     host:
       description: