lldpad: fix creation of config directory from make install

A bug fix in automake caused the method of creating the
empty /var/lib/lldpad directory (which holds the lldpad.conf
file) to fail during 'make install'.  This patch fixes the
issue.

Signed-off-by: Eric Multanen <eric.w.multanen@intel.com>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>