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

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https://hg.mozilla.org/integration/gaia-1_2/rev/ec8a6ddec821
Author: gasolin <gasolin@gmail.com>
Desc: Bug 911696 - [Dialer] [Flatfish] hide dialer app in homescreen if no telephony support