RecipeParser: always initialize ovs_conf

When the recipe doesn't contain any vlans or bonds, the corresponding
ovs_conf fields wouldn't be created. That causes the slave to crash.
This commit fixes that.

Signed-off-by: Ondrej Lichtner <olichtne@redhat.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
add ovs_vlan.xml recipe

This commit adds a new example recipe for Open vSwitch. The test follows
the example from the official Open vSwitch Configuration Cookbook on
VLANs
http://openvswitch.org/support/config-cookbooks/vlan-configuration-cookbook/

The only difference is that the recipe uses 6 machines (in my case all
virtual) instead of 2 physical hosts with 2 virtual machines each, but
the end result should be the same.

Signed-off-by: Ondrej Lichtner <olichtne@redhat.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>