[raop] Fix forgotten include of conffile.c in commit 18acb73 (fixes #688)

src/conffile.c

@@ -123,6 +123,7 @@ static cfg_opt_t sec_airplay[] =
   {
     CFG_INT("max_volume", 11, CFGF_NONE),
     CFG_BOOL("exclude", cfg_false, CFGF_NONE),
+    CFG_BOOL("permanent", cfg_false, CFGF_NONE),
     CFG_STR("password", NULL, CFGF_NONE),
     CFG_END()
   };