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

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https://hg.mozilla.org/integration/gaia-central/rev/44e3bac38280
Author: Julien Wajsberg <felash@gmail.com>
Desc: Merge pull request #16945 from julienw/980251-script-to-run-unit-tests-in-b2g

Bug 980251 - Provide a simple way to run the test runner in B2G Desktop ...

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https://hg.mozilla.org/integration/gaia-central/rev/1e4a5e68e301
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 980251 - Provide a simple way to run the test runner in B2G Desktop r=bkelly

Make bin/gaia-test takes an option to run in B2G Desktop instead of Firefox
Bumping manifests a=b2g-bump