Remove the dragonegg bots that would be duplicated if converted to 4.7.

With the recent llvm move to require gcc 4.7, it is a lot easier to keep
dragonegg building if it also requires 4.7 both for build and for the
compiler loading the plugin.

git-svn-id: https://llvm.org/svn/llvm-project/zorg/trunk@200057 91177308-0d34-0410-b5e6-96231b3b80d8