engine_page: replace netinfo to xmlrpc

Currently ovirt-node-plugin-vdsm uses vdsm netinfo
module to consult data. However, if for some reason
the connection between vdsm and libvirt is not
available vdsm kills the caller. This patch will
replace the uses of netinfo to use xmlrpc via
vdscli module.

Change-Id: I2a1243342a5f46861940dda353798e3413587969
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1097645
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>