Auto merge of #5091 - alexcrichton:update-git2, r=matklad
authorbors <bors@rust-lang.org>
Tue, 27 Feb 2018 14:24:37 +0000 (14:24 +0000)
committerbors <bors@rust-lang.org>
Tue, 27 Feb 2018 14:24:37 +0000 (14:24 +0000)
Update git2 to 0.7.0

cc #5066


Trivial merge