Update ninja to r 2ef3a546476987d6565141337c6309e7ae60f9fd

Built by running `./ninja && strip ninja` on
a (64bit) 10.6 Mac and on a 64bit linux box.
TBR=evan
Review URL: https://chromiumcodereview.appspot.com/9262002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@118205 0039d316-1c4b-4281-b951-d872f2087c98