OsmoSGSN: overview: Fix typo and reference OpenGGSN->OsmoGGSN

Change-Id: I94cc362a4f52e6bd9f93299665e73dc4fd75a2c6
diff --git a/doc/manuals/chapters/overview.adoc b/doc/manuals/chapters/overview.adoc
index 2ff92fa..abc7496 100644
--- a/doc/manuals/chapters/overview.adoc
+++ b/doc/manuals/chapters/overview.adoc
@@ -38,7 +38,7 @@
 
 === Software Components
 
-OsmoNITB contains a variety of different software components, which
+OsmoSGSN contains a variety of different software components, which
 we'll quickly describe in this section.
 
 ==== Gb Implementation
@@ -58,7 +58,7 @@
 
 ==== GTP Implementation
 
-OsmoSGSN uses the libgtp implementation originating from OpenGGSN. It
+OsmoSGSN uses the libgtp implementation originating from OsmoGGSN. It
 supports both GTPv0 and GTPv1.