xmp plugin => catch all exceptions from xdpd
of13_translation_utils::of13_map_reverse_flow_entry_instruction() and of12_translation_utils::of12_map_reverse_flow_entry_instruction() => implemented WRITE_METADATA instruction
Merge branch 'devel-0.4' into devel-0.5

Conflicts:
	src/xdpd/openflow/openflow12/of12_translation_utils.cc
	src/xdpd/openflow/openflow13/of13_translation_utils.cc