Merge branch 'vr/rebase-autosquash-does-not-imply-i'

"git rebase -p" used to pay attention to rebase.autosquash which was
wrong.  "git rebase -p -i" should, but "git rebase -p" by itself
should not.

By Vincent van Ravesteijn
* vr/rebase-autosquash-does-not-imply-i:
Do not autosquash in case of an implied interactive rebase