Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_4/rev/b16392be1d68
Author: Julien Wajsberg <felash@gmail.com>
Desc: Merge pull request #24344 from julienw/1071605-v1.4-fix-system-tests

Bug 1071605 - [System] One test is failing in v1.4: TypeError: value is ...

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https://hg.mozilla.org/integration/gaia-1_4/rev/6632dfb10a95
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 1071605 - [System] One test is failing in v1.4: TypeError: value is not a non-null object r=etienne
Bumping manifests a=b2g-bump