Mage: implement combustion nerf 50->20% for PTR 17299

git-svn-id: http://simulationcraft.googlecode.com/svn/trunk@17260 3b4652a1-8050-0410-ac47-3d40261b0f8b
Mage: should check compiling before committing...

git-svn-id: http://simulationcraft.googlecode.com/svn/trunk@17261 3b4652a1-8050-0410-ac47-3d40261b0f8b