lang/python27: Fix packaging for mips64

• Fix packaging for mips64 (Reported by: sbruno)

mips64 is also not a 32-bit ${ARCH}, so add it to the list of
architectures for which imageop.so and dl.so aren't packaged:

%%32BIT_ONLY%%lib/python2.7/lib-dynload/dl.so
%%32BIT_ONLY%%lib/python2.7/lib-dynload/imageop.so

Both dl and imageop have been removed in Python 3.x [1][2][3][4]

Thanks jhibbits@ for his help testing.

• Add BROKEN for i386 without LIBFFI option, and add upstream issue references.

While I'm here, clean up after the LIBFFI option addition:

• Sort options variables: OPTIONS_* and *_DESC
• Use OPTIONS helpers

References:

[1] The :mod:imageop module has been removed in Python 3.0.
[2] dl Added: https://hg.python.org/cpython/file/aac1ee966f56/setup.py
[3] dl Removed: https://hg.python.org/cpython/file/859ff5c7c60a/setup.py
[4] PEP-3108: https://www.python.org/dev/peps/pep-3108/

Approved by: python