Bug#194973: I also see the problem with 0.5.5.1

[sacrificial-spam-address@horizon.com]

Package: apt
Version: 0.5.5.1
Severity: important

"apt-get update" ends with:

Reading Package Lists... Error!
E: Encountered a section with no Package: header
E: Problem with MergeList /var/lib/apt/lists/_var_cache_apt-build_repository_dists_apt-build_main_binary-i386_Packages
E: The package lists or status file could not be parsed or opened.

The file is one byte long, a newline:
0000000: 0a                                       .

If I make it zero bytes long (echo -n > file), then a subsequent
"apt-get upgrade" works as opposed to failing with the same error message.

I've been truncating the file as a workaround for quite a while now,
but it is a bit annoying.  A proper fix would certainly be appreciated!