Automated checkin: version bump for fennec 20.0b6 release. DONTBUILD CLOSED TREE a=release

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branch : MOBILE200b6_2013032008_RELBRANCH
Added FENNEC_20_0b6_RELEASE FENNEC_20_0b6_BUILD1 tag(s) for changeset 829c9f566367. DONTBUILD CLOSED TREE a=release

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branch : MOBILE200b6_2013032008_RELBRANCH