test-tool: fix Inquiry.AllocLength

according to SBC-2 the alloc length should be at least 5 when
evpd is set to zero.

Also don't leak task if SPC-3 or later.

Signed-off-by: Peter Lieven <pl@kamp.de>
Merge pull request #134 from plieven/fix_inquiry

test-tool: fix Inquiry.AllocLength