python: fix on-target use of distutils/setuptools by removing references to buildpaths

python: fix on-target use of distutils/setuptools by removing references to buildpaths

Running 'python setup.py build' would fail due to the python Makefile having

CC=             i586-angstrom-linux-gcc  -m32    -march=core2 -msse3 -mtune=generic -mfpmath=sse --sysroot=/home/koen/v2012.12/build/tmp-angstrom_v2012_12-eglibc/sysroots/fri2
CXX=            i586-angstrom-linux-g++  -m32    -march=core2 -msse3 -mtune=generic -mfpmath=sse --sysroot=/home/koen/v2012.12/build/tmp-angstrom_v2012_12-eglibc/sysroots/fri2
'--with-libtool-sysroot=/home/koen/v2012.12/build/tmp-angstrom_v2012_12-eglibc/sysroots/fri2'

And more

Multiple users have reported this problem:

http://hipstercircuits.com/?p=499
http://www.gigamegablog.com/2012/09/09/beaglebone-coding-101-spi-output/

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>