git-fetch: pass --upload-pack to fetch-pack

git-fetch: pass --upload-pack to fetch-pack

Without this, there is no way to specify a remote executable when
invoking git-pull/git-fetch as there is for git-clone.

[jc: I have a mild suspicion that this is a broken environment (aka
 sysadmin disservice).  It may be legal to configure your sshd to
 spawn named program without involving shell at all, and if your
 sysadmin does so and you have your git programs under your home
 directory, you would need something like this, but then I suspect
 you would need such workaround everywhere, not just git. But we
 have these options we can use to work around the issue, so there
 is no strong reason not to reject this patch, either. ]

Signed-off-by: Michal Ostrowski <mostrows@watson.ibm.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>