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

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https://hg.mozilla.org/integration/gaia-central/rev/fb5970c10e41
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #16899 from zacc/bug_979768

Bug 979768 - Ignore StaleElementException in test_settings_wifi

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https://hg.mozilla.org/integration/gaia-central/rev/7e05ce459f7c
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Bug 979768 - Ignore StaleElementException in test_settings_wifi

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https://hg.mozilla.org/integration/gaia-central/rev/428fc4749d2a
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #16832 from jmcanterafonseca/fix_done_button

Bug 979330 - In contacts edit if the type of a field changes in the sele...

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https://hg.mozilla.org/integration/gaia-central/rev/b03f8dec0081
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Bug 979330 - In contacts edit if the type of a field changes in the selection box the done button is enabled
Bumping manifests a=b2g-bump