plugin_test.py: Don't log unsupported exceptions
plugin_test.py: Don't log unsupported exceptions

The test case will look for these when an array says
something is unsupported.  Thus we don't want to
incorrectly generate a failure when testing an
unsupported method.

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

jumitche/libstoragemgmt,jumitche/libstoragemgmt,tasleson/libstoragemgmt,tasleson/libstoragemgmt,libstorage/libstoragemgmt,jumitche/libstoragemgmt,joehandzik/libstoragemgmt,libstorage/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,lazy404/libstoragemgmt,cathay4t/libstoragemgmt,tasleson/libstoragemgmt,lazy404/libstoragemgmt,tasleson/libstoragemgmt,cathay4t/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,libstorage/libstoragemgmt,joehandzik/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,jumitche/libstoragemgmt,jumitche/libstoragemgmt,cathay4t/libstoragemgmt,joehandzik/libstoragemgmt,joehandzik/libstoragemgmt,libstorage/libstoragemgmt,libstorage/libstoragemgmt,cathay4t/libstoragemgmt,tasleson/libstoragemgmt,lazy404/libstoragemgmt,lazy404/libstoragemgmt,cathay4t/libstoragemgmt