The install_infra() call needs to be done earlier since
pip_install_gr() depends on it. Also the fact that python module names
are supposed to be lower case but some use camel case is a problem
(for example with XenAPI).
Change-Id: I7012d77134fa0d9c746d87e837934e7dcb337e5c
Closes-Bug: #1441820
9860876f5d