Bumping gaia.json for 2 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/b0fc52cca593
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #12687 from KevinGrandon/bug_923876_remove_pragma_nocache

Bug 923876 - Remove pragma no-cache from gaia applications r=vingtetun

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https://hg.mozilla.org/integration/gaia-central/rev/206f65abe48f
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 923876 - Remove pragma no-cache from gaia applications