Revert usage of install.ohmyz.sh URL, until HTTPS support.

This reverts commit b6cbba9d.

README.textile

@@ -18,11 +18,11 @@ You can install this via the command-line with either @curl@ or @wget@.
 
 h4. via @curl@:
 
-@curl -L http://install.ohmyz.sh | sh@
+@curl -L https://raw.github.com/robbyrussell/oh-my-zsh/master/tools/install.sh | sh@
 
 h4. via @wget@:
 
-@wget --no-check-certificate http://install.ohmyz.sh -O - | sh@
+@wget --no-check-certificate https://raw.github.com/robbyrussell/oh-my-zsh/master/tools/install.sh -O - | sh@
 
 h4. *Optionally*, change the install directory: