detect-ssl: suppress harmless scan-build warning

detect-ssl-version.c:271:17: warning: Value stored to 'neg' is never read
                neg = 0;

src/detect-ssl-version.c

@@ -268,7 +268,6 @@ DetectSslVersionData *DetectSslVersionParse(char *str)
                 break;
             } else {
                 SCLogError(SC_ERR_INVALID_VALUE, "Invalid value");
-                neg = 0;
                 SCFree(orig);
                 goto error;
             }