Merge remote-tracking branch 'qubesos/pr/28'

* qubesos/pr/28:
  qvm-start: exit if domain running and no --skip-if-running

qubesadmin/tools/qvm_start.py

@@ -149,6 +149,10 @@ def main(args=None, app=None):
     for domain in args.domains:
         if args.skip_if_running and domain.is_running():
             continue
+        elif domain.is_running():
+            exit_code = 1
+            parser.print_error("domain is already running")
+            return exit_code
         drive_assignment = None
         try:
             if args.drive: