Automated checkin: version bump for fennec 20.0b4 release. DONTBUILD CLOSED TREE a=release

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branch : MOBILE200b4_2013030710_RELBRANCH
Added FENNEC_20_0b4_RELEASE FENNEC_20_0b4_BUILD1 tag(s) for changeset b859178117e3. DONTBUILD CLOSED TREE a=release

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branch : MOBILE200b4_2013030710_RELBRANCH