kdiff3: fix plugin dir
kdiff3: fix plugin dir

haikuports/haikuports,Begasus/haikuports,nielx/haikuports,haikuports/haikuports,haikuports/haikuports,moochris/haikuports,nielx/haikuports,Begasus/haikuports,Begasus/haikuports,haikuports/haikuports,moochris/haikuports,haikuports/haikuports,Begasus/haikuports,Begasus/haikuports,nielx/haikuports,moochris/haikuports