Remove useless dependencies in daitch_mokotoff_header.pl.

Actually, the correct fix for this is "we don't need this at all",
because this program isn't dealing in any non-ASCII data.  The
dependency on Data::Dumper seems to be a leftover too.

Discussion: https://postgr.es/m/3287943.1680922997@sss.pgh.pa.us

contrib/fuzzystrmatch/daitch_mokotoff_header.pl

@@ -11,10 +11,6 @@
 use strict;
 use warnings;
 
-use utf8;
-use open IO => ':encoding(UTF-8)', ':std';
-use Data::Dumper;
-
 die "Usage: $0 OUTPUT_FILE\n" if @ARGV != 1;
 my $output_file = $ARGV[0];