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

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https://hg.mozilla.org/integration/gaia-2_0/rev/f6688a6c9b2e
Author: Greg Weng <snowmantw@gmail.com>
Desc: Merge pull request #21352 from snowmantw/issue1020917-2.0

Bug 1020917 - Lock screen no longer blocks home key press

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https://hg.mozilla.org/integration/gaia-2_0/rev/2036e250bfc3
Author: Greg Weng <snowmantw@gmail.com>
Desc: Bug 1020917 - Lock screen no longer blocks home key press
Bumping manifests a=b2g-bump