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

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https://hg.mozilla.org/integration/gaia-central/rev/b75fbea312c4
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #13819 from KevinGrandon/revert_bug_930104

Revert "Bug 930104 - Remove localId=0 hack for the system app on firefox and correctly set permission for any app loaded in Firefox r=vingtetun"

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https://hg.mozilla.org/integration/gaia-central/rev/5da43fdc5cc1
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Revert "Bug 930104 - Remove localId=0 hack for the system app on firefox and correctly set permission for any app loaded in Firefox r=vingtetun"

This reverts commit 09eb15afda938974376c6e33117ac84c98353bf0.