fix docs; only delete network if fwname is not provided

lib/ansible/modules/cloud/google/gce_net.py

@@ -75,7 +75,7 @@ options:
     aliases: []
   state:
     description:
-      - desired state of the persistent disk
+      - desired state of the network or firewall
     required: false
     default: "present"
     choices: ["active", "present", "absent", "deleted"]
@@ -264,7 +264,7 @@ def main():
             if fw:
                 gce.ex_destroy_firewall(fw)
                 changed = True
-        if name:
+        elif name:
             json_output['name'] = name
             network = None
             try: