Remove outdated Pyython version warning

Running omero web -h currently displays a warning about unsupported
Python 3.x versions which is obviously incorrect since version 5.6.0

omero/plugins/web.py

@@ -29,16 +29,12 @@
 from pkg_resources import resource_string
 
 from omero.install.windows_warning import windows_warning, WINDOWS_WARNING
-from omero.install.python_warning import py27_only, PYTHON_WARNING
 
 HELP = "OMERO.web configuration/deployment tools"
 
 if platform.system() == "Windows":
     HELP += "\n\n%s" % WINDOWS_WARNING
 
-if not py27_only():
-    HELP += "\n\nERROR: %s" % PYTHON_WARNING
-
 LONGHELP = """OMERO.web configuration/deployment tools
 
 Configuration:
@@ -76,8 +72,6 @@ def config_required(func):
     def import_django_settings(func):
         @windows_warning
         def wrapper(self, *args, **kwargs):
-            # if not py27_only():
-            #     self.ctx.die(681, "ERROR: %s" % PYTHON_WARNING)
             try:
                 import django  # NOQA
             except Exception: