Use git log name-status in get last commit (#16059)

* Improve get last commit using git log --name-status

git log --name-status -c provides information about the diff between a
commit and its parents. Using this and adjusting the algorithm to use
the first change to a path allows for a much faster generation of commit
info.

There is a subtle change in the results generated but this will cause
the results to more closely match those from elsewhere.

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Lauris BH <lauris@nix.lv>

vendor/github.com/djherbis/buffer/.travis.yml

@@ -0,0 +1,20 @@
+language: go
+go:
+- tip
+before_install:
+  - go get golang.org/x/lint/golint
+  - go get github.com/axw/gocov/gocov
+  - go get github.com/mattn/goveralls
+  - if ! go get code.google.com/p/go.tools/cmd/cover; then go get golang.org/x/tools/cmd/cover; fi
+script:
+  - '[ "${TRAVIS_PULL_REQUEST}" != "false" ] || $HOME/gopath/bin/goveralls -service=travis-ci -repotoken $COVERALLS_TOKEN'
+  - $HOME/gopath/bin/golint ./...
+  - go vet
+  - go test -v ./...
+notifications:
+  email:
+    on_success: never
+    on_failure: change
+env:
+  global:
+    secure: X2uEipzLOL7IDFQgiJdKQvA7gWw746gmU4HoLr73Au+mDZnIaYfpM7pR0r9S9DY23obmflOBFytB9IIyr6Ganhs8KDd6osBS3JSu5ydZKhoHDshSZHxW6GdCiR0Ya85JZ2k/CzwuZ95FcCTztXG59D8VhAoM+8gNW6VLK2mL60Y=