init: Split management_server if user used "addr:port"

If user specify in the autoinstall management_server="addr:port"
it will set the variable OVIRT_MANAGEMENT_SERVER="addr:port" in
/etc/default/ovirt which is incorrect. We should split it
and set OVIRT_MANAGEMENT_SERVER="addr" and OVIRT_MANAGEMENT_PORT="port".
This patch adds a validation into the boot schema to split the
management_server data correctly into /etc/default/ovirt schema.

Change-Id: I8b0d4055a8fd66c761a977d160422befc42019f9
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1065401
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>