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

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https://hg.mozilla.org/integration/gaia-central/rev/0757f1a86ada
Author: Fernando Campo <fernando.campo@o2.com>
Desc: Merge pull request #12710 from fcampo/ftu-doneButton-824929

Bug 824929 - [SIM screen] The Done key is always active and can be pressed before the PIN Code is introduced (r=jmcf)

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https://hg.mozilla.org/integration/gaia-central/rev/6787b9c39fcc
Author: Fernando Campo <fernando.campo@o2.com>
Desc: Bug 824929 - [SIM screen] The Done key is always active and can be pressed before the PIN Code is introduced