lock dir changed on linux from /var/lock to /run/pppd/lock with
pppd-2.5.0, which makes pppd fail to start if the distribution does not
pre-create the directory.
This reverts it back to /var/lock.
The paths for other OS should be identical as LOCALSTATEDIR should be
/var, but also revert them back as well just in case.
Since the variable is no longer used remove it from makefiles.
Fixes: 66a8c74c3f73 ("Let ./configure control the paths for pppd") Fixes: #419 Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com> Co-authored-by: Dominique Martinet <dominique.martinet@atmark-techno.com>