Allow startWatching to take in watcher connection limits

In order to allow the GerritWatcher new features for connection
limits and retry limits to be used we need to have a way to
pass those parameters to the watcher when it is constructed.

Change-Id: I199e515e7105b267acbff55a74e03cb117752bab
Merge "Allow startWatching to take in watcher connection limits"