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

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https://hg.mozilla.org/integration/gaia-central/rev/9b8fdefc90d4
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #12788 from jmcanterafonseca/fix_fb_dialog

Bug 925602 - [B2G][Contacts] No error message is given when a loss of da...

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https://hg.mozilla.org/integration/gaia-central/rev/a356cb14000c
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Bug 925602 - [B2G][Contacts] No error message is given when a loss of data connection occurs while importing Gmail contacts

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "2022c1bd0b4639d464b2385df983f84c78eca6ce", 
+    "revision": "9b8fdefc90d41d54582b1cd8c6e0aefb3e15ea5d", 
     "repo_path": "/integration/gaia-central"
 }