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

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https://hg.mozilla.org/integration/gaia-central/rev/f9bffbe55c52
Author: Germán Toro del Valle <gtorodelvalle@gmail.com>
Desc: Merge pull request #11287 from frsela/STK/Bug873906_german

Bug 873906 - [Buri][GCF][STK]case 27.22.4.13.2/1 SET UP CALL (second alpha identifier) failed (r=etiennesegonzac)

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https://hg.mozilla.org/integration/gaia-central/rev/42883f0f79f6
Author: Fernando Rodríguez Sela <frsela@tid.es>
Desc: Using mozSettings to transfer the second alpha id to the dialer

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https://hg.mozilla.org/integration/gaia-central/rev/2640ba2bec5a
Author: Greg Weng <snowmantw@gmail.com>
Desc: Merge pull request #12566 from snowmantw/issue921334

Bug 921334 - [LockScreen] The arrows on the handle is incorrect

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https://hg.mozilla.org/integration/gaia-central/rev/f18aeada0708
Author: Greg Weng <snowmantw@gmail.com>
Desc: Bug 921334 - [LockScreen] The arrows on the handle is incorrect