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

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https://hg.mozilla.org/integration/gaia-central/rev/c0c606286668
Author: Greg Weng <snowmantw@gmail.com>
Desc: Revert (manually revert) "Bug 933035 - [B2G][System][Lockscreen] The
phone goes to sleep on the lockscreen even though screen timeout is set
to never", which seems caused the Bug 980559.

    This reverts commit d808643fb7fca3fe6ffd1e415c135fe2d482e7df.
Bumping manifests a=b2g-bump