Clean up some bugs related to --limit on adhoc commands

lib/ansible/cli/adhoc.py

@@ -18,7 +18,7 @@
 ########################################################
 from ansible import constants as C
 from ansible.cli import CLI
-from ansible.errors import AnsibleOptionsError
+from ansible.errors import AnsibleError, AnsibleOptionsError
 from ansible.executor.task_queue_manager import TaskQueueManager
 from ansible.inventory import Inventory
 from ansible.parsing import DataLoader
@@ -117,10 +117,11 @@ class AdHocCLI(CLI):
             self.display.warning("provided hosts list is empty, only localhost is available")
             no_hosts = True
 
-        inventory.subset(self.options.subset)
-        if len(inventory.list_hosts()) == 0 and not no_hosts:
-            # Invalid limit
-            raise AnsibleError("Specified --limit does not match any hosts")
+        if self.options.subset:
+            inventory.subset(self.options.subset)
+            if len(inventory.list_hosts()) == 0 and not no_hosts:
+                # Invalid limit
+                raise AnsibleError("Specified --limit does not match any hosts")
 
         if self.options.listhosts:
             self.display.display('  hosts (%d):' % len(hosts))