Bumping gaia.json for 2 gaia-1_2 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_2/rev/73a45fb4fee5
Author: Ghislain 'Aus' Lacroix <aus@noiseport.org>
Desc: Merge pull request #13270 from nullaus/awesome-bar-ui

bug 925970

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https://hg.mozilla.org/integration/gaia-1_2/rev/7f78365f22ce
Author: Ghislain 'Aus' Lacroix <aus@mozilla.com>
Desc: bug 925970

* Get rid of slight shift from placeholder e.me elements and actual when in use.
* Specify font-family to use, this is unfortunately a must as we do not map our light font versions to CSS standard names.
* Degrade to older known fonts to support devices from partners that use incorrect fonts (and there are many).

r=peterla