followup fix to 38071: class missing 'frappy.' prefix

in 38071 get_class was modified not to prefix 'frappy.'
when path does not start with 'frappy'.

Change-Id: I528ed552a2af693794ce7f92c2e7dc43f4118f27
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/38435
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Georg Brandl <g.brandl@fz-juelich.de>

frappy/server.py

@@ -59,8 +59,8 @@ except ImportError:
 
 class Server:
     INTERFACES = {
-        'tcp': 'protocol.interface.tcp.TCPServer',
-        'ws': 'protocol.interface.ws.WSServer',
+        'tcp': 'frappy.protocol.interface.tcp.TCPServer',
+        'ws': 'frappy.protocol.interface.ws.WSServer',
     }
     _restart = True