apt-get update fails with 'Hash sum mismatch'.

For example:
W: Failed to fetch gzip:/var/lib/apt/lists/partial/files.freeswitch.org_repo_deb_debian_dists_sid_main_binary-amd64_Packages  Hash Sum mismatch

http://files.freeswitch.org/repo/deb/debian/dists/sid/InRelease contains:
3b775b7987d60e128780f1e979132c1a 300910 main/binary-amd64/Packages
b7014356d8a601fc827f37fa556edc9d 41654 main/binary-amd64/Packages.gz

The MD5 hashes for those files are actually:
11e5b078ef6a36ab11d94e9c7770a0aa  Packages
1925eae422f52cdaa27f4d788f7e6276  Packages.gz

I haven't checked the rest of the files, but I expect they're incorrect too.