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

========

https://hg.mozilla.org/integration/gaia-central/rev/1dc50d4916d3
Author: Michael Wu <mwu@mozilla.com>
Desc: Merge pull request #25953 from mozilla-b2g/revert-25797-bug1091483_v2.2

Revert "Bug 1091483 - Unable to show stk dialog (e.g. user confirmation ...

========

https://hg.mozilla.org/integration/gaia-central/rev/988dfa232f48
Author: Michael Wu <mwu@mozilla.com>
Desc: Revert "Bug 1091483 - Unable to show stk dialog (e.g. user confirmation dialog) ..."

========

https://hg.mozilla.org/integration/gaia-central/rev/277db9613f0c
Author: Ghislain 'Aus' Lacroix <aus@noiseport.org>
Desc: Merge pull request #25589 from nullaus/bug1077595

bug 1077595 - Use DataStoreChangeEvents to update Download API Manager c...

========

https://hg.mozilla.org/integration/gaia-central/rev/cd553f2661a4
Author: Ghislain 'Aus' Lacroix <aus@mozilla.com>
Desc: bug 1077595 - Use DataStoreChangeEvents to update Download API Manager cache up to date. Move tracking of active downloads into StatusBar instead of DownloadNotifications. r=kgrandon (system, shared), mhenretty (statusbar), arthurcc (settings)
Bumping manifests a=b2g-bump