Support remotes using the url.<base>.insteadOf scheme

When using the url.<base>.insteadOf [1] scheme `git config --get
remote.<name>.url' will return an alias instead of the actual URL.  By
using `git ls-remote --get-url <name>' the actual URL can be obtained.

 [1]: http://git-scm.com/docs/git-config

Change-Id: I4257c454daafd7bb4e60953ac520ecdab96f5d42