Merged revisions 177035 manually from

https://origsvn.digium.com/svn/asterisk/trunk

........
  r177035 | dbailey | 2009-02-18 11:24:07 -0600 (Wed, 18 Feb 2009) | 2 lines
  
  Fixed error where a check for an zero length, terminated string was needed.
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git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@177039 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/utils.c

@@ -1263,7 +1263,7 @@ void __ast_string_field_index_build_va(struct ast_string_field_mgr *mgr,
 	   otherwise, use the empty space at the end of the current
 	   pool
 	*/
-	if (fields[index][0] != '0') {
+	if (fields[index][0] != '\0') {
 		target = (char *) fields[index];
 		available = strlen(fields[index]) + 1;
 	} else {