block/ssh: remove dead code

The "err" label cannot be reached with qp != NULL.  Remove the free-ing
of qp and avoid future regressions by removing the initializer.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
ACKed-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
