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

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https://hg.mozilla.org/integration/gaia-central/rev/e1c78ea198c0
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #20740 from crdlc/bug-1026153

Bug 1026153 - [Vertical homescreen] Icon gets stuck while dragging and p...

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https://hg.mozilla.org/integration/gaia-central/rev/873dd2dc8a06
Author: crdlc <crdlc@tid.es>
Desc: Bug 1026153 - [Vertical homescreen] Icon gets stuck while dragging and pressing power button
Bumping manifests a=b2g-bump