Travis: Use secure key for IRC notification information

.travis.yml

@@ -1,5 +1,9 @@
 sudo: false
 language: cpp
+env:
+  global:
+    - secure: "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"
+
 matrix:
   fast_finish: true
   include:
@@ -79,4 +83,4 @@ script:
 notifications:
   irc:
     channels:
-    - chat.freenode.net#iotivity-node
+    - ${IRC_NOTIFICATION_CHANNEL}