revert to Cassou PPA for Emacs 24 (stable)

.travis.yml

@@ -66,9 +66,10 @@ matrix:
 ### functions compiled in.
 ###
 ### emacs24 (current stable release) is obtained from the
-### Ubuntu Emacs Lisp PPA: https://launchpad.net/~ubuntu-elisp/+archive/ppa
+### cassou PPA: http://launchpad.net/~cassou/+archive/emacs
 ###
-### emacs-snapshot (trunk) is obtained from the Ubuntu Emacs Lisp PPA.
+### emacs-snapshot (trunk) is obtained from the Ubuntu Emacs Lisp PPA:
+### https://launchpad.net/~ubuntu-elisp/+archive/ppa
 ### For the emacs-snapshot build, bleeding-edge versions
 ### of all test dependencies are also used.
 ###
@@ -98,7 +99,7 @@ install:
         sudo apt-get -qq install emacs23-gtk emacs23-el;
     fi
   - if [ "$EMACS" = 'emacs24' ]; then
-        sudo add-apt-repository -y ppa:ubuntu-elisp/ppa &&
+        sudo add-apt-repository -y ppa:cassou/emacs &&
         sudo apt-get -qq update &&
         sudo apt-get -qq -f install &&
         sudo apt-get -qq install emacs24 emacs24-el;