Expand submodule subscription support

Current sub module implementation limits the support to sites where
the canonical site name matches the server in the .gitmodules
file. Some sites run the web front end of Gerrit on a different
address than the SSH server, but they still want to utilize the
submodule subscription support.

This patch checks the [sshd] section of the gerrit.config
configuration file to extract the "proper" ssh server name. If the
server name is different from the canoncial web address Gerrit will
use the configured SSH host name when checking the .gitmodules file in
the super repository.

Change-Id: I48dc3964e130c624cc395dbe80f87f36aa8c19f8
8 files changed