Prior to this change, if a user specified a build NVR without an epoch
to compose-has-build, then compose-has-build would assume an epoch value
of "0". If the compose contained the build with a non-zero epoch, then
compose-has-build would fail to find it.

The problem is that Koji's BuildStateChange messages do not contain the
epoch at all. Koji announces builds with plain NVRs, so we don't know
what epoch value use. This means we cannot use compose-has-build with
Koji's build announcement messages if the build has a non-zero epoch.

Make compose-has-build match any epoch value in the compose.