PXB-2509: Correct CentOS 6 build errors (#1000)
PXB-2509: Correct CentOS 6 build errors (#1000)

* PXB-2509: Build libeatmydata 128 version for now

Backport fix from PS: https://github.com/Percona-Lab/ps-build/commit/9646b6f8fa63154036eabb6f0f453cdea34a1c21#diff-eac6b621a830f2b1aaee93b78a4721926ee78a9f9f9122e9fa10edd54ac34671

* PXB-2509: Correct sphinx installation for CentOS 6
Percona-Lab/jenkins-pipelines,Percona-Lab/jenkins-pipelines,Percona-Lab/jenkins-pipelines,Percona-Lab/jenkins-pipelines