libquota: remove NLS support

libquota: remove NLS support

In general libraries should never (a) call exit() or (b) print output
directly to the stdout (they might be used by GUI programs.  From (b)
follows (c), should never call internationalization functions
directly.

Also, since po/POTFILES.in wasn't edited, these strings weren't
getting included in e2fsprogs.pot for translation, so the _()
indirection didn't actually buy us anything.

We eventually need to nuke all of the log_fatal() and log_err() from
libquota, so best thing to do for now is remove NLS support
completely; no point whipsawing the translators with strings to
translate that will be disappearing soon anyway!

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>