Program Repair Shop

`compare_by_md5_sum()`

Since we're on the subject...
Purely cosmetic changes can make this function significantly easier to read

     607      my ($md5sum);
     609      my ($md5) = Digest::MD5->new;
     628        $md5->reset();
     629        $md5->addfile(MD5_fd);
     631        $md5sum = $md5->digest();

The MD5 module is expressly designed so that you can reduce this to:

        my $md5sum = Digest::MD5->new->add_file(MD5_fd)->digest;

4 lines of code and one variable are gone