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

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https://hg.mozilla.org/integration/gaia-central/rev/ec58f7b59424
Author: Greg Weng <snowmantw@gmail.com>
Desc: Merge pull request #16191 from caseyyee/bug-971392

Bug 971392 - [lockscreen] notifications not showing

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https://hg.mozilla.org/integration/gaia-central/rev/4017d5c08b7c
Author: Casey Yee <casey@caseyyee.com>
Desc: Bug 971392 - [lockscreen] notifications not showing
Bumping manifests a=b2g-bump