iser: Don't wait until iser_ib_init to init list_heads

iser_ib_init exits before initializing list heads if no IB present. This
will cause assert to fire.

see https://bugzilla.redhat.com/show_bug.cgi?id=995750

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
iser: Don't release IB resources if were not allocated

The lld exit function is being called even if the lld was not
initialized.  Added a check if IB resources were allocated before
trying to release.

Signed-off-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>