clone-pack: make it usable for partial branch cloning.
clone-pack had some logic to accept subset of remote refs from
the command line and clone from there. However, it was never
used in practice and its problems were not found out so far.
This commit changes the command to output the object names of
refs to the standard output instead of making a clone of the
remote repository when explicit <head> parameters are given; the
output format is the same as fetch-pack.
The traditional behaviour of cloning the whole repository by
giving no explicit <head> parameters stays the same.
projects / thirdparty / git.git / commit
