Merge branch 'gc/remote-with-fewer-static-global-variables'

Merge branch 'gc/remote-with-fewer-static-global-variables'

Code clean-up to eventually allow information on remotes defined
for an arbitrary repository to be read.

* gc/remote-with-fewer-static-global-variables:
  remote: die if branch is not found in repository
  remote: remove the_repository->remote_state from static methods
  remote: use remote_state parameter internally
  remote: move static variables into per-repository struct
  t5516: add test case for pushing remote refspecs