webadmin: Allow selection of None for Cloud-Init network boot protocol

The REST API supported DHCP, Static IP, and None as NIC address types
for cloud-init VM startup.  Make the same available in the UI as well.

Change-Id: Ic51a76e968922fb62a07ccaced969c8b580de083
Bug-Url: https://bugzilla.redhat.com/1120092
Signed-off-by: Greg Padgett <gpadgett@redhat.com>
Signed-off-by: Moti Asayag <masayag@redhat.com>
(cherry picked from commit d5dafab5c906c65a2878dbefd0a4b2cb8f3a1534)
core: 'Start-on-boot' of a nic should be respected

The user should be able to instruct which network interface
will be booted on startup when the interface is configured
by cloud-init. 

Change-Id: I325c5edaa27be322bd5488d4397f696338e434fe
Bug-Url: https://bugzilla.redhat.com/1132439
Signed-off-by: Moti Asayag <masayag@redhat.com>
(cherry picked from commit cf8f8106ca83c33721a6c61ec2ce297bd828d0b6)