Bumping gaia.json for 4 gaia-central revision(s) a=gaia-bump

Bumping gaia.json for 4 gaia-central revision(s) a=gaia-bump
Truncated some number of revisions since the previous bump.

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https://hg.mozilla.org/integration/gaia-central/rev/a1cbfe5e2473
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #12969 from zacc/bug_928864

Bug 928864 - Reenable python ui test test_gallery_delete_image.py , Mari...

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https://hg.mozilla.org/integration/gaia-central/rev/ccf46db548ed
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Bug 928864 - Reenable python ui test test_gallery_delete_image.py , Marionette modal dialog handling repaired

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https://hg.mozilla.org/integration/gaia-central/rev/fd2544cad200
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #12968 from zacc/bug_928834

Bug 928834 - Python - Change the timing of the base select wrapper to re...

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https://hg.mozilla.org/integration/gaia-central/rev/33babafa1834
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Bug 928834 - Python - Change the timing of the base select wrapper to resolve test failure in clock app