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

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https://hg.mozilla.org/integration/gaia-central/rev/a1e288daa17c
Author: EragonJ <eragonj@eragonj.me>
Desc: Merge pull request #19221 from EragonJ/bug-1007469

Bug 1007469 - copy-build-stage-manifest should depend on $(XULRUNNER_BAS...

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https://hg.mozilla.org/integration/gaia-central/rev/9c8e679372a0
Author: EragonJ <eragonj@eragonj.me>
Desc: Bug 1007469 - copy-build-stage-manifest should depend on $(XULRUNNER_BASE_DIRECTORY)
Bumping manifests a=b2g-bump