shift_sjis_2004 related autority files are remaining

Hi, I happned to notice that backend/utils/mb/Unicode directory
contains two encoding authority files, which I believe are not to
be there.

euc-jis-2004-std.txt
sjis-0213-2004-std.txt

And what is more astonishing, make distclean didn't its work.

| $ make distclean
| rm -f

The Makefile there is missing the defenition of TEXT.

# Sorry for the bogus patch by me..

The attached is the *first patch* that fixes distclean and adds
the two files into GENERICTEXTS.

=====

I don't attach the *second* patch since it's too large for the
trivality and can be made by the following steps.

$ cd src/backend/utils/mb/Unicode
$ git rm *.txt
$ git commit

regards,

--
Kyotaro Horiguchi
NTT Open Source Software Center