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/README.MacOSX b/README.MacOSX
index 0a904cd..a8c4776 100644
--- a/README.MacOSX
+++ b/README.MacOSX
@@ -1,4 +1,4 @@
-OpenGGSN/Mac OS X notes
+OsmoGGSN/Mac OS X notes
 
 Mac OS X support is experimental, please test and report bugs. The
 Mac OS X port is tested on Mac OS X 10.3.5, but may also work on