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

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https://hg.mozilla.org/integration/gaia-central/rev/9864dda0b7f3
Author: Luke Chang <lchang@mozilla.com>
Desc: Merge pull request #26738 from luke-chang/1105977_sms_unsent_discard_useless

Bug 1105977 - [FFOS2.0][Woodduck][SMS] The discard function is wrong, r=steveck

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https://hg.mozilla.org/integration/gaia-central/rev/c7373e08a637
Author: Luke Chang <lchang@mozilla.com>
Desc: Bug 1105977 - [FFOS2.0][Woodduck][SMS] The discard function is wrong

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "c1280c482bf1a35091bf279294d6f277255d8960", 
+    "revision": "9864dda0b7f391987d0ae746068b4790d2ffb4d4", 
     "repo_path": "integration/gaia-central"
 }