Drop unused common_vty.c

Change-Id: I19f1ece5f2f62d1f8f40a9b9d0c6c41ad05e5c76
diff --git a/debian/copyright b/debian/copyright
index 8094f2a..65f3ba7 100644
--- a/debian/copyright
+++ b/debian/copyright
@@ -123,7 +123,6 @@
            src/gprs/sgsn_libgtp.c
            src/gprs/sgsn_main.c
            src/gprs/sgsn_vty.c
-           src/libcommon/common_vty.c
            src/libcommon/debug.c
            src/libcommon/gsm_data.c
            src/libcommon/gsm_data_shared.c