Make type and len class attributes of OFPInstructionMeter

Make type and len class attributes of OFPInstructionMeter
and update JSON accordingly.

This is in keeping with the implementation of other OFPInstruction classes.

Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
ofproto_v1_2_parser: put some assertions

Put some assertions to catch usage mistakes earlier.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
ofproto_v1_3_parser: put some assertions

Put some assertions to catch usage mistakes earlier.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>