Automated checkin: version bump for firefox 20.0b2 release. DONTBUILD CLOSED TREE a=release

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branch : GECKO200b2_2013022709_RELBRANCH
Added FIREFOX_20_0b2_RELEASE FIREFOX_20_0b2_BUILD1 tag(s) for changeset f45f4b3cba11. DONTBUILD CLOSED TREE a=release

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branch : GECKO200b2_2013022709_RELBRANCH