export_create will not map a LUN if it's already mapped to in the target, even if attempting to map to a different initiator name in acls/

[clarkhale]

I've submitted this bug for RHEL, but it also exists in the current version:
https://bugzilla.redhat.com/show_bug.cgi?id=1445536

If I want to map a LUN to two different initiators in the same target, create_export does not behave as expected:

jsonrequest('export_create', dict(pool=pool, vol='test18', initiator_wwn='iqn.2006-03.com.wtf.ohyeah:661', lun=1))
jsonrequest('export_create', dict(pool=pool, vol='test18', initiator_wwn='iqn.2006-03.com.wtf.ohyeah:662', lun=1))

I'd expect to see:

  o- iscsi ...................................................................... [Targets: 1]
  | o- iqn.2007-11.net.deadvax.nfs:auto ............................................ [TPGs: 1]
  |   o- tpg1 ......................................................... [no-gen-acls, no-auth]
  |     o- acls .................................................................... [ACLs: 2]
  |     | o- iqn.2006-03.com.wtf.ohyeah:661 ................................. [Mapped LUNs: 1]
  |     | | o- mapped_lun1 .................................... [lun0 block/my_vg:test18 (rw)]
  |     | o- iqn.2006-03.com.wtf.ohyeah:662 ................................. [Mapped LUNs: 1]
  |     |   o- mapped_lun1 .................................... [lun0 block/my_vg:test18 (rw)]

But instead I see:

  | o- iqn.2007-11.net.deadvax.nfs:auto ............................................ [TPGs: 1]
  |   o- tpg1 ......................................................... [no-gen-acls, no-auth]
  |     o- acls .................................................................... [ACLs: 2]
  |     | o- iqn.2006-03.com.wtf.ohyeah:661 ................................. [Mapped LUNs: 1]
  |     | | o- mapped_lun1 .................................... [lun0 block/my_vg:test18 (rw)]
  |     | o- iqn.2006-03.com.wtf.ohyeah:662 ................................. [Mapped LUNs: 0]

[tasleson]

Fixed with merged #20