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

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https://hg.mozilla.org/integration/gaia-central/rev/0b5ae2b554bc
Author: Bob Silverberg <bob.silverberg@gmail.com>
Desc: Merge pull request #18651 from bobsilverberg/b2g_start_v1.3

Bug 1000334 - Adjust b2g_start to work for v1.3 as well

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https://hg.mozilla.org/integration/gaia-central/rev/be191de20706
Author: Bob Silverberg <bob.silverberg@gmail.com>
Desc: Bug 1000334 - Adjust b2g_start to work for v1.3 as well
Bumping manifests a=b2g-bump