Adjust for deprecation of which(1)

debian/aoetools.postinst

@@ -4,7 +4,7 @@ set -e
 
 case "$1" in
 configure)
-    if which udevadm >/dev/null; then
+    if command -v udevadm >/dev/null; then
         udevadm control --reload || true
     fi
     # load the kernel module (as opposed to letting the init script do it)