Add starlingx-gerritbot config

The StarlingX project decided to move the gerritbot notifications into
a dedicated IRC channel. This change applies that change to the config
files.

Change-Id: I74b82bfdd4497d4f61126c07e1045e316bbc798a
Signed-off-by: Ildiko Vancsa <ildiko.vancsa@gmail.com>

accessbot/channels.yaml

@@ -275,6 +275,7 @@ channels:
   - name: senlin
   - name: solum
   - name: starlingx
+  - name: starlingx-gerritbot
   - name: storyboard
   - name: surveil
   - name: swiftonfile

gerritbot/channels.yaml

@@ -1696,7 +1696,7 @@ solum:
   branches:
     - master
 
-starlingx:
+starlingx-gerritbot:
   events:
     - patchset-created
     - change-merged