ofp-errors: Duplicate instruction error

Add OFPERR_OFPBIC_DUP_INST (type = OFPET_BAD_INSTRUCTION, code = 9)
and use it for OpenFlow1.4+.

For OpenFlow1.1 - 1.3 map this error to ONFBIC_DUP_INSTRUCTION
(experimenter = ONF, type = 2600) which is proposed in
OpenFlow enhancement proposal EXT-260 "Add error
code for duplicate instruction.".

Previously ONFBIC_DUP_INSTRUCTION was used for OpenFlow1.3+.

Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Ben Pfaff <blp@nicira.com>