OFPT_ERROR_MSG can return truncated messages. Some users want to
see them in human-friendly format [1]. Catch exceptions caused
by such truncated messages and reraise as OFPTruncatedMessage
with incomplete ofpmsg in the exception class.
[1] https://bugs.launchpad.net/dragonflow/+bug/1624826
Signed-off-by: IWAMOTO Toshihiro <iwamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>