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

========

https://hg.mozilla.org/integration/gaia-central/rev/897ebc324cd5
Author: Bob Silverberg <bob.silverberg@gmail.com>
Desc: Merge pull request #13388 from zacc/bug_935041

Bug 935041 - Investigate test_sms_add_contact failure, resolve and re-en...

========

https://hg.mozilla.org/integration/gaia-central/rev/bfe3328d3051
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Bug 935041 - Investigate test_sms_add_contact failure, resolve and re-enable the test

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "6745e7046ff9a18195746fb2f0f46f71b0db4cc2", 
+    "revision": "897ebc324cd5f6b3cf556197f4541ba54b1af7e3", 
     "repo_path": "/integration/gaia-central"
 }