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

========

https://hg.mozilla.org/integration/gaia-central/rev/be11a5a50fb6
Author: Ghislain 'Aus' Lacroix <aus@noiseport.org>
Desc: Merge pull request #19299 from nullaus/bug982295-browser-api

bug 982295 - Use new Browser API download method. r=benfrancis

========

https://hg.mozilla.org/integration/gaia-central/rev/64cb2dd6c146
Author: Ghislain 'Aus' Lacroix <aus@mozilla.com>
Desc: bug 982295 - Use new Browser API download method. r=benfrancis

========

https://hg.mozilla.org/integration/gaia-central/rev/8e6260f8ec20
Author: vingtetun <21@vingtetun.org>
Desc: Merge pull request #20161 from theres-waldo/bug1020045

Bug 1020045 - Turn on APZ overscrolling by default. r=kats

========

https://hg.mozilla.org/integration/gaia-central/rev/d664e90c679c
Author: Botond Ballo <botond@mozilla.com>
Desc: Bug 1020045 - Turn on APZ overscrolling by default. r=kats
Bumping manifests a=b2g-bump