Ilo drivers sets capabilities:boot_mode in node properties
if there is none.
For a node capable of booting in both bios and uefi, setting
of this property by driver prevents it from getting selected for
future deploys requests for other boot mode.
It would be selected only for deploy requests where flavor
extra_specs specifies capabilities:boot_mode with a value
matching with one set by driver in the node properties.
Closes-Bug: 1418327
Change-Id: I90571487840c6a74699a8fbfbac8035c3efb5672