oe-setup-rpmrepo: add native sysroot so nativepython can be found by env

This avoids the following new behavior resulting from the create_wrapper
fixes:

  llc[11]$ ../poky/scripts/oe-setup-rpmrepo
  /usr/bin/env: nativepython: No such file or directory

(From OE-Core rev: ce37ef05c14ba28773823d1f14f629c37c76d827)

Signed-off-by: Peter A. Bigot <pab@pabigot.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/oe-setup-rpmrepo

@@ -90,6 +90,7 @@ if [ ! -e "$CREATEREPO" ]; then
 	exit 1
 fi
 
+export PATH=${PATH}:${OECORE_NATIVE_SYSROOT}/usr/bin
 
 $CREATEREPO "$RPM_DIR"