Allow using the serial number of a node as an additional matching criteria for the bus_order [1/3]

This introduces a new optional attribute "serial_number" in the interface_maps
of the network barclamp (+ the needed change to make use of that in the crowbar
and deployer barclamps) that can be use as additional matching criteria for
defining the interface order for a certain node. (This is helpful e.g. if two
nodes with the same value for "Product Name" need to have different
interface_map defined)


 chef/cookbooks/barclamp/libraries/barclamp_library.rb | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

Crowbar-Pull-ID: ead8713cdc2ce28d97bab36901b28238e32bb08e

Crowbar-Release: pebbles