install gtp-tunnel and gtp-link tools

This eases quick setup for demonstration purposes.

Change-Id: I674c463989bc1529bfe132b7ec0df7a0052169df
diff --git a/debian/libgtpnl-tools.install b/debian/libgtpnl-tools.install
new file mode 100644
index 0000000..49983e4
--- /dev/null
+++ b/debian/libgtpnl-tools.install
@@ -0,0 +1,2 @@
+/usr/bin/gtp-link
+/usr/bin/gtp-tunnel