Cleanup: Remove unnecessary double-semicolons.

Cleanup: Remove unnecessary double-semicolons.

The entries were found by the following command line:

$ find . -regex ".*\.[cChH]\(pp\)?" | xargs git grep -e ';;' --and --not
-e 'for *(.*;;'

Which is a combination of http://stackoverflow.com/a/3858879 and
http://gitster.livejournal.com/27674.html

BUG=None
R=mtklein@google.com

Review URL: https://codereview.chromium.org/1088763005