tools/check: No need to check for ${PYTHON} existence.

It must exist as otherwise the build will fail since we reference
$(PYTHON) all over the place. Furthermore the fallback of
'/usr/bin/env python' actually runs Python, it doesn't get the path to
it. So that wouldn't work very well.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

tools/check/check_python

@@ -3,10 +3,6 @@
 
 . ./funcs.sh
 
-if test -z ${PYTHON}; then
-	PYTHON=`/usr/bin/env python 2>/dev/null`
-fi
-
 ${PYTHON} -c '
 import sys
 sys.exit(sys.version_info[0] < 2 or sys.version_info[1] < 2)