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

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https://hg.mozilla.org/integration/gaia-central/rev/4ecf4e9ff552
Author: Yuren Ju <yurenju@gmail.com>
Desc: Merge pull request #14199 from Rik/change-reporter-944279

Bug 944279 - Use the spec reporter for all mocha suites r=yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/27953e157311
Author: Anthony Ricaud <anthony@ricaud.me>
Desc: Bug 944279 - Use the spec reporter for all mocha suites

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https://hg.mozilla.org/integration/gaia-central/rev/76adbd1c8de0
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #13953 from jmcanterafonseca/fix_dialer_call_log_fb

Bug 940000 - Align call log and dialer FB number recognition with bug 93...

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https://hg.mozilla.org/integration/gaia-central/rev/864ae8009dff
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Bug 940000 - Align call log and dialer FB number recognition with bug 937552