tests: remove redundant sed filtering

tests: remove redundant sed filtering

Now that the majority of device name filtering is in filter.sed,
it does not need to be specified explicitly for every test.

Fix the error message printed in debugfs when opening the device
to match that used in other tools.  This simplifies the filtering,
and will be helpful if debugfs messages are internationalized.

[ Fixed up some test failures in m_hugefile t_uninit_bg_rm --tytso ]

Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>