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

========

https://hg.mozilla.org/integration/gaia-central/rev/798ac2c58dbf
Author: Florin Strugariu <bebef_1987@yahoo.com>
Desc: Merge pull request #21585 from viorelaioia/bug_1036962

Bug 1036962 - Replace time.sleep(5) in test_settings_power_save_mode.py ...

========

https://hg.mozilla.org/integration/gaia-central/rev/2918e110f0dc
Author: Viorela Ioia <viorelaioia@gmail.com>
Desc: Bug 1036962 - Replace time.sleep(5) in test_settings_power_save_mode.py with a suitable wait
Bumping manifests a=b2g-bump