Automated checkin: version bump for firefox 26.0 release. DONTBUILD CLOSED TREE a=release

--HG--
branch : GECKO260_2013120510_RELBRANCH
Added FIREFOX_26_0_RELEASE FIREFOX_26_0_BUILD2 tag(s) for changeset 39faf812aaec. DONTBUILD CLOSED TREE a=release

--HG--
branch : GECKO260_2013120510_RELBRANCH