Use ZMQ only since testing for CORBA did not really work out.

Belonging to [master]:
  - OpenModelica/OMCompiler#2507

Author: dietmarw

Examples/generate_icons.py

@@ -39,14 +39,8 @@
 from optparse import OptionParser
 
 import svgwrite
-try:
-  from OMPython import OMCSession
-  omc = OMCSession()
-  print("Using CORBA")
-except ImportError:
-  from OMPython import OMCSessionZMQ
-  omc = OMCSessionZMQ()
-  print("No CORBA interface found, using ZMQ instead")
+from OMPython import OMCSessionZMQ
+omc = OMCSessionZMQ()
 
 # OpenModelica setup commands
 OMC_SETUP_COMMANDS = ['setCommandLineOptions("-d=nogen,noevalfunc")']