Text fixes

Fixed typos and text issues:
htts -> https
ovirt -> oVirt (as per style of http://www.ovirt.org)
ovirt-engine -> oVirt (for consistency between CentOS and Fedora)

Change-Id: I06fda5e0cd7abc9dfd04c55532b9438f9554b2ca
Signed-off-by: Allon Mureinik <amureini@redhat.com>