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

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https://hg.mozilla.org/integration/gaia-central/rev/42cea8ba40f1
Author: James Burke <jrburke@gmail.com>
Desc: Merge pull request #15635 from jrburke/bug962969-email-use-src-for-deps

Bug 962969 -- [email] build: make_gaia_shared.js should use source dir for shared dependency scanning r=asuth

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https://hg.mozilla.org/integration/gaia-central/rev/3ca089dba513
Author: jrburke <jrburke@gmail.com>
Desc: Bug 962969 -- [email] build: make_gaia_shared.js should use source dir for shared dependency scanning
Bumping manifests a=b2g-bump