apt: Do not install /var/log/apt for target

/var/log is normally a link to /var/volatile/log and /var/volatile is a
tmpfs mount. So anything created in /var/log will not be available when
the tmpfs is mounted.

Also some whitespace clean up.

Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>