Make shell main() specify return value in exit code

sys.exit() calls in main() will make the interactive
python interpreter exit. We can call the main() as
below to avoid to exit the interactive interpreter,
and specify the return value of main() in the exit
code at the same time.
sys.exit(main())

also see: I6ead9853fe27e99df3e9121478e906a06839f48c

Change-Id: I3086dc0529c4343f246f543de1b6ee6540438a98

senlinclient/shell.py

@@ -308,13 +308,13 @@ def main(args=None):
         SenlinShell().main(args)
     except KeyboardInterrupt:
         print(_("... terminating senlin client"), file=sys.stderr)
-        sys.exit(130)
+        return 130
     except Exception as e:
         if '--debug' in args or '-d' in args:
             raise
         else:
             print(encodeutils.safe_encode(six.text_type(e)), file=sys.stderr)
-        sys.exit(1)
+        return 1
 
 if __name__ == "__main__":
-    main()
+    sys.exit(main())