Add log from sync integration tests to .gitignore.

R=atwilson@chromium.org
BUG=None

Review URL: https://codereview.chromium.org/159753010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250756 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250756