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

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https://hg.mozilla.org/integration/gaia-central/rev/d6c6223196a9
Author: evelynhung <jj.evelyn@gmail.com>
Desc: Merge pull request #13229 from bcbcarl/bug860424

Bug 860424 - Show first 8 characters only, r=evelyn

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https://hg.mozilla.org/integration/gaia-central/rev/22116b9a7011
Author: Carl X. Su <bcbcarl@gmail.com>
Desc: Bug 860424 - Show first 8 characters only

Signed-off-by: Carl X. Su <bcbcarl@gmail.com>