Remove build properties for subtree spliting.

We won't subtree split again. Tasks were removed from build.xml already.

build.properties

@@ -4,10 +4,6 @@ project.name = CakePHP
 # Git stuff
 git.remote = origin
 
-# Subtree split repo locations
-git.subtree.app = git@github.com:cakephp/app.git
-git.subtree.framework = git@github.com:cakephp/cakephp.git
-
 # Directories
 build.dir = build
 dist.dir = dist