multipath: and wwids_file multipath.conf option

multipath: and wwids_file multipath.conf option

This patch adds a wwids_file multipath.conf option, so that users can
move the wwids file from its default location at /etc/multipath/wwids.
It also corrects the default bindings file location in the multipath.conf
manpage and makes the bindings_file value always print out when you
display the configuration, like is done with the other default values.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>