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

========

https://hg.mozilla.org/integration/gaia-central/rev/64405c99369f
Author: RickyChien <ricky060709@gmail.com>
Desc: Merge pull request #18850 from RickyChien/bug-998776-follow-up

Bug 998776 - Follow-up, update gaia_node_modules.revision r=@RickyChien

========

https://hg.mozilla.org/integration/gaia-central/rev/c412ba5a2f4b
Author: Ricky Chien <ricky060709@gmail.com>
Desc: Bug 998776 - Follow-up, update gaia_node_modules.revision
Bumping manifests a=b2g-bump