qvm-template: improve error reporting

Do not print the whole traceback by default - do that only when
--verbose is used.

qubesadmin/tools/qvm_template.py

@@ -1477,6 +1477,7 @@ def main(args: typing.Optional[typing.Sequence[str]] = None,
     if p_args.updatevm is UPDATEVM:
         p_args.updatevm = app.updatevm
 
+    try:
         if p_args.refresh:
             qrexec_repoquery(p_args, app, refresh=True)
 
@@ -1509,6 +1510,10 @@ def main(args: typing.Optional[typing.Sequence[str]] = None,
             repolist(p_args, app)
         else:
             parser.error('Command \'%s\' not supported.' % p_args.command)
+    except Exception as e:  # pylint: disable=broad-except
+        print('ERROR: ' + str(e), file=sys.stderr)
+        app.log.debug(str(e), exc_info=sys.exc_info())
+        return 1
 
     return 0