unit tests for invalid args skipped

[Kota Tsuyuzaki]

current liberasurecode unit test runs only when the args is provided [1]. However, most of invalid args unit tests doesn't take the args[2] and it uses EC_BACKENDS_MAX[3] which causes NULL args that makes the test skipping.

1: https://github.com/openstack/liberasurecode/blob/master/test/liberasurecode_test.c#L2021
2: https://github.com/openstack/liberasurecode/blob/master/test/liberasurecode_test.c#L484
3: https://github.com/openstack/liberasurecode/blob/master/test/liberasurecode_test.c#L1549

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/387879
Committed: https://git.openstack.org/cgit/openstack/liberasurecode/commit/?id=e8b5a64d8d68c6f379fcd8aa69d934682b9e1a25
Submitter: Jenkins
Branch: master

commit e8b5a64d8d68c6f379fcd8aa69d934682b9e1a25
Author: Kota Tsuyuzaki <email address hidden>
Date: Tue Oct 18 02:10:01 2016 -0700

    Fix liberasurecode skipping a bunch of invalid_args tests

    Since the commit a01b1818c874a65d1d1fb8f11ea441e9d3e18771,
    we have been to able to test some parameters for each tests.
    However, instead, the NULL which means the end of the test parameters
    causes skipping a bunch of unit tests which doesn't take args (e.g.
    test_create_backend_invalid_args). That is the worse because we have not
    tested anymore for the tests since the commit.

    This patch fixes to make it tested and more, fix a minor bug for a
    case that corrupted header incomming to get_metadata.

    Closes-Bug: #1634403
    Change-Id: Ib99a8aa6032f02d0c7d1ab94b8da1ebfd9047d74