Automated checkin: version bump for firefox 21.0b2 release. DONTBUILD CLOSED TREE a=release

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branch : GECKO210b2_2013040819_RELBRANCH
Added FIREFOX_21_0b2_RELEASE FIREFOX_21_0b2_BUILD1 tag(s) for changeset c4dfe07f855c. DONTBUILD CLOSED TREE a=release

--HG--
branch : GECKO210b2_2013040819_RELBRANCH