added missing why2-test's outputBuffer deallocation

so now if you don't count that fucking json-c library, there are no memory leaks

FUCK YES

src/lib/test/main.c

@@ -91,6 +91,7 @@ int main(void)
     free(textBuffer);
     free(keyBuffer);
     free(statusBuffer);
+    free(outputBuffer);
     deallocateOutput(encrypted);
 
     return exitCode;