Merge branch 'cr/push-force-tag-update'

Regression fix to stop "git push" complaining "target ref already
exists", when it is not the real reason the command rejected the
request (e.g. non-fast-forward).

* cr/push-force-tag-update:
push: fix "refs/tags/ hierarchy cannot be updated without --force"

diff --cc cache.h
Simple merge

diff --cc remote.c
Simple merge