vhost-scsi: fix usage of error_reportf_err()

vhost-scsi: fix usage of error_reportf_err()

It is required to use error_report() instead of error_reportf_err(), if the
prior function does not take local_err as the argument. As a result, the
local_err is always NULL and segment fault may happen.

vhost_scsi_start()
-> vhost_scsi_set_endpoint(s) --> does not allocate local_err
-> error_reportf_err()
   -> error_vprepend()
      -> g_string_append(newmsg, (*errp)->msg) --> (*errp) is NULL

In addition, add ": " at the end of other error_reportf_err() logs.

Fixes: 7962e432b4e4 ("vhost-user-scsi: support reconnect to backend")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Message-Id: <20231214003117.43960-1-dongli.zhang@oracle.com>
Reviewed-by: Feng Li <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>