Apply Justin Riley's ACCEPT_KEYWORDS patch.

Apply Justin Riley's ACCEPT_KEYWORDS patch.

Excerpts from Justin's comments [1]:

At least for Portage 2.1.4.4, /usr/lib64/portage/pym/portage.py's
config class specifically excludes ACCEPT_KEYWORDS. Therefore,
  ENV = portage_config(clone=portage_settings).environ()
will never contain ACCEPT_KEYWORDS argument and the arch will always
be ~x86 as the result of get_keyword().

...

After looking at the code, it appears that the PORTAGE_CONFIG variable
introduced in the previous patch can completely replace ENV.  Here's
the patch that simply changes:

  ENV = portage_config(clone=portage_settings).environ()

to

  ENV = portage_config(clone=portage_settings)

[1]: http://code.google.com/p/g-pypi/issues/detail?id=4