Use openflowjava-supplied MAC address utilities

The implementations provided here are trivial and do not perform as well
as they could. openflowjava has optimized versions of these, so use
those.

Change-Id: I895b9e2d0268b8497590438195c644c97967abfe
Signed-off-by: Robert Varga <robert.varga@pantheon.sk>
Merge "Use openflowjava-supplied MAC address utilities"