ofp-actions: Update "copy_field" to latest OF1.5 draft.

Since my original prototype, the oxm_id_len field was removed and
replaced by 2 bytes of padding.

ONF-JIRA: EXT-320
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Thomas Graf <tgraf@noironetworks.com>
ofp-actions: Add support for ONF extension actions.

Preparation for supporting ONFACT_ET_COPY_FIELD.

ONF-JIRA: EXT-320
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Thomas Graf <tgraf@noironetworks.com>
ofp-actions: Support "copy_field" ONF extension to OpenFlow 1.3.

ONF-JIRA: EXT-320
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Thomas Graf <tgraf@noironetworks.com>