file.c: missing "custom" sound files should not generate warning logs

With `sounds_search_custom_dir = yes` we first look to see if a sound file
is present in the "custom" sound directory before looking in the standard
sound directories.  We should not be issuing a WARNING log message if a
sound cannot be found in the "custom" directory.

Resolves: https://github.com/asterisk/asterisk/issues/1170

main/file.c

@@ -787,13 +787,8 @@ static int fileexists_core(const char *filename, const char *fmt, const char *pr
 	return 0;
 }
 
-struct ast_filestream *ast_openstream(struct ast_channel *chan, const char *filename, const char *preflang)
-{
-	return ast_openstream_full(chan, filename, preflang, 0);
-}
-
-struct ast_filestream *ast_openstream_full(struct ast_channel *chan,
-	const char *filename, const char *preflang, int asis)
+static struct ast_filestream *openstream_internal(struct ast_channel *chan,
+	const char *filename, const char *preflang, int asis, int quiet)
 {
 	/*
 	 * Use fileexists_core() to find a file in a compatible
@@ -822,7 +817,9 @@ struct ast_filestream *ast_openstream_full(struct ast_channel *chan,
 	if (!fileexists_core(filename, NULL, preflang, buf, buflen, file_fmt_cap) ||
 		!ast_format_cap_has_type(file_fmt_cap, AST_MEDIA_TYPE_AUDIO)) {
 
-		ast_log(LOG_WARNING, "File %s does not exist in any format\n", filename);
+		if (!quiet) {
+			ast_log(LOG_WARNING, "File %s does not exist in any format\n", filename);
+		}
 		ao2_ref(file_fmt_cap, -1);
 		return NULL;
 	}
@@ -845,6 +842,17 @@ struct ast_filestream *ast_openstream_full(struct ast_channel *chan,
 	return NULL;
 }
 
+struct ast_filestream *ast_openstream(struct ast_channel *chan, const char *filename, const char *preflang)
+{
+	return openstream_internal(chan, filename, preflang, 0, 0);
+}
+
+struct ast_filestream *ast_openstream_full(struct ast_channel *chan,
+	const char *filename, const char *preflang, int asis)
+{
+	return openstream_internal(chan, filename, preflang, asis, 0);
+}
+
 struct ast_filestream *ast_openvstream(struct ast_channel *chan,
 	const char *filename, const char *preflang)
 {
@@ -1307,7 +1315,7 @@ int ast_streamfile(struct ast_channel *chan, const char *filename,
 	if (ast_opt_sounds_search_custom && !is_absolute_path(filename)) {
 		memset(custom_filename, 0, sizeof(custom_filename));
 		snprintf(custom_filename, sizeof(custom_filename), "custom/%s", filename);
-		fs = ast_openstream(chan, custom_filename, preflang);
+		fs = openstream_internal(chan, filename, preflang, 0, 1); /* open stream, do not warn for missing files */
 		if (fs) {
 			tmp_filename = custom_filename;
 			ast_debug(3, "Found file %s in custom directory\n", filename);