Fix timeout(1) usage in wsrep_sst_mariabackup on *BSD

Also fix the usage of timeout(1) on NetBSD, OpenBSD and DragonFly.

scripts/wsrep_sst_mariabackup.sh

@@ -803,7 +803,8 @@ recv_joiner()
     if [ $tmt -gt 0 ]; then
         if [ -n "$(commandex timeout)" ]; then
             local koption=0
-            if [ "$OS" = 'FreeBSD' ]; then
+            if [ "$OS" = 'FreeBSD' -o "$OS" = 'NetBSD' -o "$OS" = 'OpenBSD' -o \
+                 "$OS" = 'DragonFly' ]; then
                 if timeout 2>&1 | grep -qw -F -- '-k'; then
                     koption=1
                 fi