tester.c: Update 'check' usage
tester.c: Update 'check' usage

The unit test library check made a change which emits warnings
when 'fail_unless' is passed a message.  For more information
see:

https://github.com/libcheck/check/pull/298/commits/82540c5428d3818b64d6a8aefb601e722520651f

As we compile with warnings as errors, we fail to compile when
using check >= 0.15.0.

Remove use of deprecated 'fail_unless'.

Signed-off-by: Tony Asleson <1ef2d381aa56d512126ddaacc29e68136e4fdf55@redhat.com>

cathay4t/libstoragemgmt,tasleson/libstoragemgmt,libstorage/libstoragemgmt,tasleson/libstoragemgmt,cathay4t/libstoragemgmt,tasleson/libstoragemgmt,libstorage/libstoragemgmt,libstorage/libstoragemgmt,libstorage/libstoragemgmt,tasleson/libstoragemgmt,cathay4t/libstoragemgmt,tasleson/libstoragemgmt,libstorage/libstoragemgmt,cathay4t/libstoragemgmt,cathay4t/libstoragemgmt