Remove 1.x pre-GA versions from yum repos

[andrewkroh]

It seems that pre-GA versions confuse some implementations of the rpmvercmp algorithm (i.e. it thinks 1.0.0~beta4 is newer than 1.0.0).

To mitigate the issue we should remove the pre-GA versions from the repo.

See: https://discuss.elastic.co/t/beats-repo-and-spacewalk/36043