abi/debian: Bump ABI version of libgtp after struct size change

The gsn_t changed the size with the addition of the ctrl pointer.
Bump the SO version to not break osmo-sgsn/ggsn on upgrade.

Call the -dev package libgtp-dev to follow the rest of Osmocom and
to ease making releases here.

Change-Id: Iac4d6d2effde1a6b2f60b1e1b49c91513d5ca8c3
diff --git a/debian/changelog b/debian/changelog
index a00671b..5d52bfd 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,8 +1,9 @@
 openggsn (0.93) UNRELEASED; urgency=medium
 
   * Bump version to ease upgrading from Debian SID.
+  * Bump libgtp SO version after ABI change.
 
- -- Holger Hans Peter Freyther <holger@moiji-mobile.com>  Tue, 24 May 2016 22:53:16 +0200
+ -- Holger Hans Peter Freyther <holger@moiji-mobile.com>  Tue, 24 Jan 2017 17:26:26 +0100
 
 openggsn (0.92) precise; urgency=medium