ofp-errors: Add OFPET_FLOW_MONITOR_FAILED

Add OFPET_FLOW_MONITOR_FAILED which is added in OpenFLow1.4.
Map the OFPERR_NXBRC_FM_* errors to the corresponding new OpenFlow errors.

This is a step towards supporting OpenFlow1.4 flow monitors.

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