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

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https://hg.mozilla.org/integration/gaia-central/rev/2e293f22489f
Author: Corey Frang <gnarf37@gmail.com>
Desc: Bug 926587 - [B2G][Clock][Stopwatch] Choppy transition animation going to Stopwatch from Timer or Alarm - r=jugglinmike

- Implements a temporary workaround while waiting for Bug 921317 to be resolved in the platform