virt.cartesian_config: Fix a typo in this module

Signed-off-by: Qingtang Zhou <qzhou@redhat.com>
qemu.qemu_guest_agent: Update service start cmd for RHEL.6

The qemu-guest-agent service name is 'qemu-ga' on RHEL.6
system, so it needs a special config.

Signed-off-by: Qingtang Zhou <qzhou@redhat.com>
Merge pull request #564 from zhouqt/minor-fix

qemu: Some minor fix for qemu test