ssl-opt.sh: Preserve proxy log, too, if --preserve-logs is specified

tests/ssl-opt.sh

@@ -682,6 +682,9 @@ run_test() {
     if [ "$PRESERVE_LOGS" -gt 0 ]; then
         mv $SRV_OUT o-srv-${TESTS}.log
         mv $CLI_OUT o-cli-${TESTS}.log
+        if [ -n "$PXY_CMD" ]; then
+            mv $PXY_OUT o-pxy-${TESTS}.log
+        fi
     fi
 
     rm -f $SRV_OUT $CLI_OUT $PXY_OUT