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

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https://hg.mozilla.org/integration/gaia-central/rev/18cb453adefa
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #15541 from darkowlzz/bug-930607

Bug 930607 - The phone number is emptied even when the call can't be made. r=etienne

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https://hg.mozilla.org/integration/gaia-central/rev/81dfbe9aa31d
Author: sunny <indiasuny000@gmail.com>
Desc: Bug 930607 - The phone number is emptied even when the call can't be made
Bumping manifests a=b2g-bump