Fix incorrect check for DTLS

Missing wildcards meant that some servers were not identified as DTLS,
which lead to port checking on TCP rather than UDP, and thus mistakenly
cancelling tests as the server had not come up.

Signed-off-by: Paul Elliott <paul.elliott@arm.com>

tests/ssl-opt.sh

@@ -601,7 +601,7 @@ wait_client_done() {
 # check if the given command uses dtls and sets global variable DTLS
 detect_dtls() {
     case "$1" in
-        *dtls=1*|-dtls|-u) DTLS=1;;
+        *dtls=1*|*-dtls*|*-u*) DTLS=1;;
         *) DTLS=0;;
     esac
 }