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

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https://hg.mozilla.org/integration/gaia-central/rev/892533d0008f
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #12881 from viorelaioia/bug-925850

Bug 925850 - Modify the test_dialer_make_call assertion to handle long phone numbers

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https://hg.mozilla.org/integration/gaia-central/rev/3a5a27c118aa
Author: Viorela Ioia <viorelaioia@gmail.com>
Desc: Bug 925850 - Modify the test_dialer_make_call assertion to handle long phone numbers