Simplify configWriter to use netmodels

configwriter add methods were using tons of parameters. It would be
simpler if they were to use netmodels info.

Patch Set 2: clean up the netmodels configurator interaction.

Patch Set 4: Changed bond and bridge properties to use isinstance.

Change-Id: Id9e00f6a8ce21a2e0bf24ad2cd13af6fe3d3f356
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/16324
Reviewed-by: Mark Wu <wudxw@linux.vnet.ibm.com>
Reviewed-by: Giuseppe Vallarelli <gvallare@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>