Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/98929825123f
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 929172 - gaia unit tests broken in b2g desktop due to fast CSP enhancement r=yurenju

* registers special /common and /shared directories
* changes httpd.js to handle correctly registered directories
* changes the test-agent boilerplate to always use the test's hostname
* add a NO_LOCK_SCREEN env variable for disabling the lockscreen at build time
* add a "unit tests in b2g" travis job
* This simplifies also how localization is done
* enable the Promise object in all DEBUG=1 profiles
Bumping manifests a=b2g-bump