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

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https://hg.mozilla.org/integration/gaia-central/rev/504dcc988234
Author: Fernando Rodríguez Sela <frsela@tid.es>
Desc: Merge pull request #12362 from frsela/STK/Bug910151

Bug 910151 - [Buri][REG][STK]should display the default text when execute get input command with default text parameter, r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/d95fcedf6d31
Author: Fernando Rodríguez Sela <frsela@tid.es>
Desc: Bug 910151 - [Buri][REG][STK]should display the default text when execute get input command with default text parameter

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "f161d4a6b878b706e73dddaedd5aca8c126222f6", 
+    "revision": "504dcc988234a2a29bb1b370ec3a2046d86d63c5", 
     "repo_path": "/integration/gaia-central"
 }