package.bbclass: fix directories setuid and setgid bits
populate_packages relies on ``mkdir`` to both create a directory and set
its permissions. However, ``mkdir`` honors the ``umask`` value.
Therefore, some bits may be lost in the operation. In our case, the
setgid bit on the directories were lost.
This commit fixes this by having a distinct call to create the directory
and to set the permissions.
Signed-off-by: Jean-Tiare Le Bigot <jean-tiare.le-bigot@easymile.com> Signed-off-by: Armin Kuster <akuster808@gmail.com>
