Add missing UNITTESTS

There is no need for test functions to be build in normal code.

src/util-rule-vars.c

@@ -99,6 +99,7 @@ char *SCRuleVarsGetConfVar(const char *conf_var_name,
 
 
 /**********************************Unittests***********************************/
+#ifdef UNITTESTS
 
 static const char *dummy_conf_string =
     "%YAML 1.1\n"
@@ -421,6 +422,8 @@ end:
     return result;
 }
 
+#endif /* UNITTESTS */
+
 void SCRuleVarsRegisterTests(void)
 {