handle telnet_init_default() error case

Closes: CID#307532
Change-Id: I0210b535b844529e217fd5d6ffb01f94a262dc9c
diff --git a/src/e1_recorder.c b/src/e1_recorder.c
index 68d4543..996ede4 100644
--- a/src/e1_recorder.c
+++ b/src/e1_recorder.c
@@ -207,8 +207,12 @@
 		exit(1);
 	}
 
-	/* start telne tafte reading config for vty_get_bind_adr() */
-	telnet_init_default(rec_tall_ctx, NULL, 4444);
+	/* start telnet after reading config */
+	rc = telnet_init_default(rec_tall_ctx, NULL, 4444);
+	if (rc < 0) {
+		fprintf(stderr, "Cannot open telnet server port: %s\n", strerror(errno));
+		exit(1);
+	}
 
 	while (1) {
 		osmo_select_main(0);