The arguments to the N_() macro must only ever be a literal string. It
is not possible to use macro arguments, or use macro string
concatenation in this context. The N_() macro is a no-op whose only
purpose is to act as a marker for xgettext when it extracts translatable
strings from the source code. Anything other than a literal string will
be silently ignored by xgettext.

Unfortunately this means that the clever MSG, MSG2 & MSG_EXISTS macros
used for building up error message strings have prevented any of the
error messages getting marked for translation. We must sadly, revert to
a more explicit listing of strings for now.
Reviewed-by: NJiri Denemark <jdenemar@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>