staging: lustre: fix conctl.c issues found by Klocwork Insight tool

The function lst_test_add_ioctl is always copying lstio_tes_param
from userland even if the user doesn't send this data to LNet
selftest. Only consider lstio_tes_param data if lstio_tes_param_len
is not zero.
Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4629
Reviewed-on: http://review.whamcloud.com/9386Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Isaac Huang <he.huang@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lnet/selftest/conctl.c

@@ -761,6 +761,11 @@ static int lst_test_add_ioctl(lstio_test_args_t *args)
 		LIBCFS_ALLOC(param, args->lstio_tes_param_len);
 		if (!param)
 			goto out;
+		if (copy_from_user(param, args->lstio_tes_param,
+				   args->lstio_tes_param_len)) {
+			rc = -EFAULT;
+			goto out;
+		}
 	}
 
 	rc = -EFAULT;
@@ -769,9 +774,7 @@ static int lst_test_add_ioctl(lstio_test_args_t *args)
 	    copy_from_user(src_name, args->lstio_tes_sgrp_name,
 			   args->lstio_tes_sgrp_nmlen) ||
 	    copy_from_user(dst_name, args->lstio_tes_dgrp_name,
-			   args->lstio_tes_dgrp_nmlen) ||
-	    copy_from_user(param, args->lstio_tes_param,
-			   args->lstio_tes_param_len))
+			   args->lstio_tes_dgrp_nmlen))
 		goto out;
 
 	rc = lstcon_test_add(batch_name, args->lstio_tes_type,