ofctl_v1_2/3: IP arbitrary bitmask support

Openflow 1.1 and later versions allow the use of IP address with
arbitrary bitmask in match fields. This adds arbitrary bitmask
support to related functions.

After applying this patch, it's no longer compatible with ACL
hybrid CIDR format (Cisco-like ACL bitmasks) because such format
exists only in some router's ACL configuration.

Reported-by: Yi-Ching Lee <potatoching11@gmail.com>
Reported-by: Li-Der Chou <cld@csie.ncu.edu.tw>
Signed-off-by: Wei-Li Tang <alextwl@xinguard.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
ofp_event: fix a typo

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