target: Indicate success if writing 0 to pi_prot_type
target: Indicate success if writing 0 to pi_prot_type

See https://bugzilla.redhat.com/show_bug.cgi?id=1240687

Returning 0 from a configfs store function results in infinite retries.

Reported-by: Yanko Kaneti <03eb6af71fbb3dc3105ee7a9182911b06509f2d9@declera.com>
Signed-off-by: Andy Grover <b7d524d2f5cc5aebadb6b92b08d3ab26911cde33@redhat.com>
Signed-off-by: Nicholas Bellinger <978acd1567d5598152161fdf8bf3ca568f950c9b@linux-iscsi.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs