Remove unused connection properties
Remove unused connection properties

Refactor iSCSI connect is was introduced in this patch:
  https://review.openstack.org/#/c/455393/.

The method _connect_vol is used for parallelize logins, we shouldn't
give these arguments('target_portals', 'target_iqns', 'target_luns');
and it will also make a mess in the debug message in _connect_vol.
So, just kick them out.

Change-Id: I76fc7645bfe00c3b1653fce4eace8a6430930ad2

openstack/os-brick,openstack/os-brick