Bug#4590: dpkg version compare with epochs is broken

[Guy Maor <maor@ece.utexas.edu>]

Package: dpkg
Version: 1.4.0

dpkg compares falsely when the implict 0 epoch is made explicit.

$ dpkg --compare-versions '0:2' eq '0:2' ; echo $?
1
$ dpkg --compare-versions '1:2' gt '0:2' ; echo $?
1
$ dpkg --compare-versions '1:2' eq '0:2' ; echo $?
0