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

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https://hg.mozilla.org/integration/gaia-central/rev/f08155be032c
Author: Julien Wajsberg <felash@gmail.com>
Desc: Merge pull request #20281 from julienw/1023147-wait-firefox

Bug 1023147 - On Travis, wait longer for Firefox r=yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/788787b478cd
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 1023147 - On Travis, wait longer for Firefox r=yurenju
Bumping manifests a=b2g-bump