Default to http protocol for server url.
Default to http protocol for server url.

Currently, rbtools assumes that the reviewboard server url is given with http
protocol. This results in an error connecting to the server despite the fact
that the url given is valid. This problem will arise if http protocol is not
given in either the config file(.reviewboardrc) or in the input with rbt
setup-repo command.

Now, the url will default to http protocol if no protocol is given. This
prevents url retrieve from the config file or from the setup-repo command input
from throwing connection not found error message when the correct url is given.

Testing Done:
Tested rbt setup-repo and config file with and without the http protocol. E.g.
“localhost:8080” and “http://localhost:8080”. Worked fine for both with
different commands.

Tested with invalid url. E.g. “htp://localhost:8080” . Valid error message
shown.

Ran unit tests.

Bugs closed: 3718

Reviewed at https://reviews.reviewboard.org/r/6817/

datjwu/rbtools,reviewboard/rbtools,halvorlu/rbtools,datjwu/rbtools,davidt/rbtools,halvorlu/rbtools,reviewboard/rbtools,davidt/rbtools,haosdent/rbtools,haosdent/rbtools,beol/rbtools,davidt/rbtools,haosdent/rbtools,datjwu/rbtools,beol/rbtools,halvorlu/rbtools,reviewboard/rbtools,beol/rbtools