MDEV-23580 addendum: normal operation in configurations where stunnel is not available

Author: sysprg

scripts/wsrep_sst_common.sh

@@ -368,7 +368,7 @@ EOF
 
  # first, the normal directories, so that we can detect incompatible protocol
  RC=0
- eval rsync "'${STUNNEL:+--rsh=$STUNNEL}'" \
+ eval rsync ${STUNNEL:+--rsh=\"$STUNNEL\"} \
  --owner --group --perms --links --specials \
  --ignore-times --inplace --dirs --delete --quiet \
  $WHOLE_FILE_OPT $FILTER "'$WSREP_SST_OPT_DATA/'" \