package/owfs: fixup Python sysconfigdata for per-package directories

This is needed so that building the owfs Python module uses the gcc
from owfs per-package directory, and not the one from the python
per-package directory.

Fixes:

  http://autobuild.buildroot.net/results/0d582dda367507991a4c38141db36b0fa8e47e67/



Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>