Do some trivial cleanup of the _hgcmd method.
Do some trivial cleanup of the _hgcmd method.

Not all these parameters were used, and the name itself was kind of annoying.
Simple cleanup.

Testing done: Ran unit tests

Reviewed at https://reviews.reviewboard.org/r/5117/

beol/rbtools,haosdent/rbtools,reviewboard/rbtools,halvorlu/rbtools,reviewboard/rbtools,davidt/rbtools,reviewboard/rbtools,1tush/rbtools,halvorlu/rbtools,beol/rbtools,davidt/rbtools,halvorlu/rbtools,haosdent/rbtools,beol/rbtools,datjwu/rbtools,datjwu/rbtools,haosdent/rbtools,datjwu/rbtools,davidt/rbtools