Move setting Nicira datapath ID out of kernel.

Move setting Nicira datapath ID out of kernel.

When generating the datapath id/mac address for an OpenFlow device, the
kernel checks the DMI for a suitable one in a Nicira UUID.  If one is
not found, then a random address is generated.  This patch makes it so
that a random address is always generated.  The DMI Nicira UUID check is
now done in the init script, which overrides the random address
generated when the datapath was created.  Ripping code out of the kernel
is good.