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

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https://hg.mozilla.org/integration/gaia-central/rev/a6ece290b974
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #15509 from steveck-chung/bug-950623

Bug 950623 - [Messages] Multi-recipient. Back button is kept as pressed after going back from recipients details list. r=julienw

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https://hg.mozilla.org/integration/gaia-central/rev/ed0fa41a84ec
Author: Steve Chung <schung@mozilla.com>
Desc: Bug 950623 - [Messages] Multi-recipient. Back button is kept as pressed after going back from recipients details list

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "d15adbd5c5b14787893d40e4f7d13aca057b9df6", 
+    "revision": "a6ece290b97430be9fafb4a53bafe24f2fe5f0b4", 
     "repo_path": "/integration/gaia-central"
 }