Bumping gaia.json for 7 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/b8b563023919
Author: b2gautomation <jonallengriffin@gmail.com>
Desc: Update gaia-ui-tests.json; Merge pull request #1366 from zacc/rename_actions_activities

Rename the Actions class to Activities to represent the correct nomencla...

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https://hg.mozilla.org/integration/gaia-central/rev/c3b0cba3f280
Author: b2gautomation <jonallengriffin@gmail.com>
Desc: Merge branch 'master' of github.com:mozilla-b2g/gaia

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https://hg.mozilla.org/integration/gaia-central/rev/da1dbdf53180
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #12190 from alivedise/bugzilla/912796/lockscreen-meets-attentionscreen

Bug 915468 - Back to main screen when attention screen is shown, r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/d53922f63bd1
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 915468 - Back to main screen when attention screen is shown

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https://hg.mozilla.org/integration/gaia-central/rev/aa1336177168
Author: b2gautomation <jonallengriffin@gmail.com>
Desc: Merge branch 'master' of github.com:mozilla-b2g/gaia

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https://hg.mozilla.org/integration/gaia-central/rev/09ca45c6bb91
Author: b2gautomation <jonallengriffin@gmail.com>
Desc: Merge branch 'master' of github.com:mozilla-b2g/gaia

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https://hg.mozilla.org/integration/gaia-central/rev/019abe60d05c
Author: b2gautomation <jonallengriffin@gmail.com>
Desc: Update gaia-ui-tests.json; Merge pull request #1364 from bebef1987/pep8

PEP8 review

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "d05ca1f81793a8d1b12eee32158bf045c3446d51", 
+    "revision": "b8b563023919dc91f344eec8acabbeb00991fcfd", 
     "repo_path": "/integration/gaia-central"
 }