Fix bug which caused ascend_open() to return "I/O error" (instead of "not me").

(This happened if ascend_open was called with *err != 0).

svn path=/trunk/; revision=34588

wiretap/ascendtext.c

@@ -107,6 +107,7 @@ static gint64 ascend_seek(wtap *wth, int *err)
     excessive_read_count--;
 
     if (!excessive_read_count) {
+      *err = 0;
       return -1;
     }