Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/d6c2abfbf3c8
Author: Wes Kocher <kwierso@gmail.com>
Desc: Revert "Merge pull request #30610 from janus926/bug-1174629" for breaking device reboot tests during perf testing

This reverts commit 8a1e4ae522c121c5cacd39b20a5386ec9055db82, reversing
changes made to f3d5c6c9cfb51556ecb62a7ebec6ee23d24ffffb.

b2g/config/gaia.json

@@ -1,9 +1,9 @@
 {
     "git": {
-        "git_revision": "d5e91593150d4a7d51d3bed96bc4632bff90b754", 
+        "git_revision": "20bfbbca4b3df4fee66629ff4547c2c3079333c2", 
         "remote": "https://git.mozilla.org/releases/gaia.git", 
         "branch": ""
     }, 
-    "revision": "26c6ac388ac117f9b4bf3b3b4f67aafe209f566e", 
+    "revision": "d6c2abfbf3c86394c8517c2c31167e1c5a37aa97", 
     "repo_path": "integration/gaia-central"
 }