doc: removed include of osi_reference.adoc

Signed-off-by: Stefan Cyliax <stefan.cyliax@asam.net>

Author: Stefan Cyliax

doc/open-simulation-interface_user_guide.adoc

@@ -115,5 +115,3 @@ include::./setup/installing_windows_python.adoc[leveloffset=+2]
 //== Improving performance
 
 //TODO: Define topics and issues regarding performance.
-
-include::./misc/osi_reference.adoc[leveloffset=+1]