fixed cert generation

vpngen.py

 import os.path
 import re
 import shutil
+from enum import Enum
 from subprocess import call
 
 
-class VpnGenError:
+class VpnGenError(Enum):
     Success = 0,
     VpnAlreadyExists = 1,
     VpnDoesNotExists = 2,
 
         call([".%sclean-all" % os.sep])
         call([pkitool, "--initca"])
-        call([pkitool, "server"])
+        call([pkitool, "server", "-batch"])
         call([".%sbuild-dh" % os.sep])
         call(["openssl", "ca", "-gencrl",
               "-keyfile", "keys%sca.key" % os.sep,