git diff adds the following line to diffs:
\ No newline at end of file

which interferes with diff.py parsing. diff.py only looks for '+', '-'
and ' ' at the beginning of the line.

Issue seen on https://gerrit.chromium.org/gerrit/68611

Change-Id: I0d7b4485c470e0b409f2c9cddde6c9aceba0152e