Rename OpenGGSN to OsmoGGSN

Osmocom has maintained this program since about 7 years now, while
the original author / copyright holder has completely disappeared.

With the introduction of Osmocom-style CTRL and VTY interfaces,
the way how the program is used and configured has substantially
changed.  In order to avoid confusion in terms of configuration file
format etc, let's rename it to OsmoGGSN.

Change-Id: I2da30f7d4828e185bfac1a4e2d8414b01cbe4f9d
diff --git a/.gitignore b/.gitignore
index 111fa98..6885cd3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,13 +15,13 @@
 libtool
 ltmain.sh
 missing
-openggsn.spec
+osmo-ggsn.spec
 stamp-h1
 doc/Makefile.in
 ggsn/Makefile.in
 gtp/Makefile.in
 sgsnemu/Makefile.in
-debian/openggsn/
+debian/osmo-ggsn/
 debian/*.debhelper
 debian/libgtp/
 debian/*.log
@@ -33,7 +33,7 @@
 debian/files
 debian/libgtp-dev/
 libgtp.pc
-ggsn/ggsn
+ggsn/osmo-ggsn
 m4/
 *.swp
 *.o