Add python-tasklib to centos.ks.erb/ubuntu_packages

* python-tasklib should be installed on provisioning stage
  for every distro

Related to blueprint granular-deployment-based-on-tasks

Change-Id: Ic195c7d66cd625d795fdb3b27369d408b8ca3fa1
Merge "Add python-tasklib to centos.ks.erb/ubuntu_packages"