oeqa/utils/decorators: Append the testname without the full path

oeqa/utils/decorators: Append the testname without the full path

When getting the failures/errors/skipped lists, include the
unit test without the full path.

This issue was found on this scenario

    | test_1_logrotate_setup (oeqa.runtime.logrotate.LogrotateTest) ... FAIL
    | test_2_logrotate (oeqa.runtime.logrotate.LogrotateTest) ... ok

Where test_1_logrotate failed and test_2_logrotate should not have
run because

    @skipUnlessPassed("test_1_logrotate_setup")
    def test_2_logrotate(self):

Signed-off-by: Leonardo Sandoval <leonardo.sandoval.gonzalez@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>