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

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https://hg.mozilla.org/integration/gaia-central/rev/5f56d333d78c
Author: George <georgeiscoming@gmail.com>
Desc: Merge pull request #18731 from cctuan/999413

Bug 999413 - clean useless files when execute make

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https://hg.mozilla.org/integration/gaia-central/rev/c7162584b3c3
Author: cctuan <georgeiscoming@gmail.com>
Desc: Bug 999413 - clean useless files when execute make
Bumping manifests a=b2g-bump