tests: add settle wait before issue remove

Some older BB with older cryptsetup tool do not 'retry' on remove
and when  remove is issued right after 'fsck'  - it might be
rejected with:

Device @PREFIX@-tcrypt2 is busy.

Try to use udevadm settle.

test/shell/fsadm-crypt.sh

@@ -83,6 +83,7 @@ export LVM_BINARY
 test ! -d "$mount_dir" && mkdir "$mount_dir"
 
 crypt_close() {
+	aux udev_wait
 	cryptsetup remove "$1"
 	if [ "$?" -eq 0 -a -n "$DROP_SYMLINK" ]; then
 		rm -f "$DM_DEV_DIR/mapper/$1"