Update local tracking refs when pushing- no way to disable

In this commit:
b516968ff62ec153e008d033c153affd7ba9ddc6

I don't know if anyone else has the same way of working as I do, but I
tend to set the "remote.<name>.skipDefaultUpdate" property to true for
my publicly visible repository, just so I don't have duplicate branch
heads lying around in my local repository. Call this peculiar, but I
like it that way. However, git-push does not respect this property,
meaning I know have these branches whether I want them or not. In a
tool such as qgit or even 'git branch -a' output, it starts to get
awful cluttered.

I'm not terribly familiar with GIT internals, so I don't know that I
am the best to make a patch for this, but I'll take no response as a
answer that I should start coding something up. Please CC me on
emails, I'm not on the GIT mailing list.

-Dan