test: make sure udev isn't opening a device before closing it.

As we open and close so quickly, udev might still have the device
open.  so call udevsettle before stopping an array during testing.

Signed-off-by: NeilBrown <neilb@suse.de>

test

@@ -77,6 +77,9 @@ fi
 # mdadm always adds --quiet, and we want to see any unexpected messages
 mdadm() {
     rm -f $targetdir/stderr
+    case $* in
+       *-S* ) udevsettle;;
+    esac
     case $* in
        *-C* ) $mdadm 2> $targetdir/stderr --quiet "$@" --auto=yes;;
         * )   $mdadm 2> $targetdir/stderr --quiet "$@"