agent: Build and install ovirt guest agent on Ubuntu

Implemented necessary changes for making the oVirt Guest Agent
working on Ubuntu and Fedora.

Change-Id: I7a694bf1f7ff4230bac305dd571899265ef63950
Signed-off-by: Zhou Zheng Sheng <zhshzhou@linux.vnet.ibm.com>
Signed-off-by: Vinzenz Feenstra <vfeenstr@redhat.com>