Use archive.apache.org to ensure reproducible builde

While rebuilding the 5.9.0.redhat-610379 version locally, I got this error:

org.apache.maven.wagon.ResourceDoesNotExistException: File: http://www.eu.apache.org/dist/activemq/activemq-cpp/source/activemq-cpp-library-3.8.2-src.tar.gz , ReasonPhrase:Not Found.

That particular artifact is no longer available at that location. Typically, the main Apache download site only contains the latest version of every artifact, so it would be better to use http://archive.apache.org/dist instead.