fix manual run of source service

A service explicit called via singlerun could get skipped otherwise,
if the service is defined with a different mode.

eg. running

  osc service mr download_files

to update and merge files after a version update, but the project has a
global download_files service configured for validation.

osc/core.py

@@ -464,6 +464,9 @@ def _execute(
             allservices = [data]
         elif singleservice:
             allservices = [s for s in allservices if s['name'] == singleservice]
+            # set the right called mode or the service would be skipped below
+            for s in allservices:
+                s['mode'] = callmode
 
         if not allservices:
             # short-circuit to avoid a potential http request in vc_export_env