staging/lustre: Correct default for LUSTRE_TRANSLATE_ERRNOS

LUSTRE_TRANSLATE_ERRNOS is never enabled, a "true" is not a valid value.
Use "default y" instead of "default true" to fix this.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>