nvme-fabrics: prevent overriding of existing host

JIRA: https://issues.redhat.com/browse/RHEL-30850

When first connecting a target using the "default" host parameters, setting the hostid from the command line during a subsequent connection establishment would override the "default" hostid parameter. This would cause an existing connection that is already using the host definitions to lose its hostid.

To address this issue, the code has been modified to allow only 1:1 mapping between hostnqn and hostid. This will maintain unambiguous host identification. Any non 1:1 mapping will be rejected during connection establishment.

Signed-off-by: John Meneghini jmeneghi@redhat.com