Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/25ef69cde9ca
Author: Carsten Book -Tomcat- <cbook@mozilla.com>
Desc: Revert "Bug 937442 - (lockscreen-window) [Window Management] Implement LockscreenWindow to manage LockScreen." for gaia unit test failures

This reverts commit 71e9afea939cca5c664dad671c9270c66384f274.
Bumping manifests a=b2g-bump