verify-bashisms: explicitly shut down server

Current tinfoil2 requires manually shutting down the server.
Without that, the script hangs during exit. This might change
in the future.

(From OE-Core rev: 62f42ce063115f4a02c219e323252223818a150f)

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/verify-bashisms

@@ -114,3 +114,4 @@ if __name__=='__main__':
             for message,source in results:
                 print(" %s\n  %s" % (message, source))
             print()
+    tinfoil.shutdown()