fix some more compiler warnings
diff --git a/openbsc/src/vty_interface.c b/openbsc/src/vty_interface.c
index 9aa9706..894146b 100644
--- a/openbsc/src/vty_interface.c
+++ b/openbsc/src/vty_interface.c
@@ -620,7 +620,7 @@
       "show e1_timeslot [line_nr] [ts_nr]",
 	SHOW_STR "Display information about a E1 timeslot\n")
 {
-	struct e1inp_line *line;
+	struct e1inp_line *line = NULL;
 	struct e1inp_ts *ts;
 	int ts_nr;