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

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https://hg.mozilla.org/integration/gaia-1_3/rev/55b99ce9f94b
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #17129 from etiennesegonzac/bug-981468-callgroup-keypad

Bug 981468 - Fixing JS erros occuring while using the keypad during a conference call. r=ferjm
Bumping manifests a=b2g-bump