Automated checkin: version bump for fennec 21.0b4 release. DONTBUILD CLOSED TREE a=release

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branch : MOBILE210b4_2013042323_RELBRANCH
Added FENNEC_21_0b4_RELEASE FENNEC_21_0b4_BUILD1 tag(s) for changeset 89ebccb1acde. DONTBUILD CLOSED TREE a=release

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branch : MOBILE210b4_2013042323_RELBRANCH