Remove duplicate configure-vm call in create-nodes

create-nodes duplicated the entire configure-vm call based on the
setting of $BRIDGE, to add an argument. There is an existing pattern for
that behaviour which means complex command lines don't have to be
duplicated.

Change-Id: I0f843b0be36aa13644953099cc109dee8d5e2ab3
Merge "Remove duplicate configure-vm call in create-nodes"