GGSN: don't say 'NITB'

Change-Id: I960ce8ee749621176ceaa556a1fe93b54e08b6fc
diff --git a/doc/manuals/chapters/running.adoc b/doc/manuals/chapters/running.adoc
index cff3f8d..a242e36 100644
--- a/doc/manuals/chapters/running.adoc
+++ b/doc/manuals/chapters/running.adoc
@@ -1,4 +1,4 @@
-== Running OsmoNITB
+== Running OsmoGGSN
 
 The OsmoGGSN executable (`osmo-ggsn`) offers the following command-line
 arguments: