Bumping gaia.json for 3 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/3b61e1b2ec16
Author: Gabriele Svelto <gsvelto@mozilla.com>
Desc: Merge pull request #25778 from gabrielesvelto/bug-834530-emergency-dtmf

Bug 834530 - Improvements to the emergency and dialer keypad touch tones

========

https://hg.mozilla.org/integration/gaia-central/rev/37b43eaf36dc
Author: Gabriele Svelto <gsvelto@mozilla.com>
Desc: Bug 834530 - Make the TonePlayer handle the channel sounds will be played on r=drs

========

https://hg.mozilla.org/integration/gaia-central/rev/42e7158b01f0
Author: Gabriele Svelto <gsvelto@mozilla.com>
Desc: Bug 834530 - Import fixes for audible tones, dialtones and tactile feedback from the shared dialer r=drs
Bumping manifests a=b2g-bump