Remove setuptools hack for installation prefix

Not working any longer. setuptools installation is deprecated anyway.

setup.py

@@ -1,5 +1,4 @@
 from setuptools import setup, Command
-from setuptools.command.install import install as orig_install
 from distutils.command.build import build as orig_build
 
 from subprocess import call
@@ -49,26 +48,8 @@ def make_mo(self, po_filename, mo_filename):
             logging.warning(e)
 
 
-# NOTE: Subclassing the setuptools install command alters its behaviour to use
-# the distutils code. This is due to some really odd call-context checks in
-# the setuptools command.
-#
-# In fact this is desirable because distutils (correctly) installs data files
-# to `sys.prefix` whereas setuptools by default installs to the egg folder
-# (which is pretty much useless) and doesn't invoke build commands before
-# install. The only real drawback with the distutils behaviour is that it does
-# not automatically install dependencies, but we can easily live with that.
-#
-# Note further that we need to subclass the *setuptools* install command
-# rather than the *distutils* one to prevent errors when installing with pip
-# from the source distribution.
-class install(orig_install):
-    pass
-
-
 setup(
     cmdclass={
-        'install': install,
         'build': build,
         'build_mo': build_mo,
     },