setuptools: this is in the main yocto layer now, remove

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>

classes/setuptools.bbclass

@@ -1,8 +0,0 @@
-inherit distutils
-
-DEPENDS += "python-setuptools-native"
-
-DISTUTILS_INSTALL_ARGS = "--root=${D} \
-    --single-version-externally-managed \
-    --prefix=${prefix} \
-    --install-data=${datadir}"