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

========

https://hg.mozilla.org/integration/gaia-central/rev/49747f365043
Author: Florin Strugariu <florin.strugariu@softvision.ro>
Desc: Merge pull request #25894 from viorelaioia/bug_1090281_1

Bug 1090281 - Investigate failure in test_setup_and_send_imap_email.py

========

https://hg.mozilla.org/integration/gaia-central/rev/1153e3a9a97e
Author: Viorela Ioia <viorelaioia@gmail.com>
Desc: Bug 1090281 - Investigate failure in test_setup_and_send_imap_email.py
Bumping manifests a=b2g-bump