RPC Tweaks

I made a couple of changes to `appengine_rpc.py` to make it work for me:

* My password had some characters that didn't play well with the curl command construction, this adds quotes to make sure they aren't interpreted when the command is invoked
* The URL construction was adding an additional `s` to the scheme, so I tweaked the scheme construction to ensure that it never results in a scheme of `httpss`