meta/lib/oe/package.py: fix files ownership in packages

This fix solves the problem with the ownership of files in packages.
The do_install task was producing correct and expected output but when
the files were being put in, e.g. a rpm package, the ownership could
be different than that in the do_install task.

[YOCTO #7428]

Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com>
Signed-off-by: Fabrice Coulon <fabrice.coulon@axis.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>