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

========

https://hg.mozilla.org/integration/gaia-central/rev/b7daaa59c505
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #22553 from gasolin/issue-973441-5

Bug 973441 - [settings] refactor Date & Time panel with AMD pattern, r=arthur

========

https://hg.mozilla.org/integration/gaia-central/rev/093bc6761325
Author: gasolin <gasolin@gmail.com>
Desc: Bug 973441 - [settings] refactor Date & Time panel with AMD pattern
- use class instead of id
- fix tz_select loading
- re-organize keys
- implement attachListeners
- add unit test
- have a DateTime module for setting date, time, and time zone
- apply observable to whole modules/date_time
- move datePickerChange/timePickerChange into module
- move event handler to panel and autoUpdateDate/Time to DateTime module
- move UI to panel
- auto date/time observer
- fix auto switch
- add formatDate and formatTime
- use settings addObserver

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "06c7c071929cab4b8591767f7522040946356226", 
+    "revision": "b7daaa59c505bf87cbb31ba97b4a8683d2606219", 
     "repo_path": "/integration/gaia-central"
 }