remove an XXX comment

- we can't use ast_true here because non-empty strings would no longer be
   evaluated as true
document the return values of pbx_checkcondition() in doxygen format


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@25411 65c4cc65-6c06-0410-ace0-fbb531ad65f3

pbx.c

@@ -5486,7 +5486,7 @@ int pbx_checkcondition(const char *condition)
 		return 0;
 	else if (*condition >= '0' && *condition <= '9')	/* Numbers are evaluated for truth */
 		return atoi(condition);
-	else	/* Strings are true -- XXX maybe use ast_true() ? */
+	else	/* Strings are true */
 		return 1;
 }