sw test tool: Fix to compare OFPMatch ignoring masks that are all one bits

OF 1.3.3 spec (7.2.3.5 Flow Match Field Masking) says:

    An all-zero-bits oxm_mask is equivalent to omitting the OXM TLV entirely. An all-one-bits oxm_mask
    is equivalent to specifying 0 for oxm_hasmask and omitting oxm_mask.

This patch fixes to compare OFPMatch ignoring masks that are all one bits.

Reported-by: Arne Goetje <arne_goetje@accton.com>
Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
sw test tool: Fix to compare OFPMatch ignoring fields that masks are all zero bits

OF 1.3.3 spec (7.2.3.5 Flow Match Field Masking) says:

    An all-zero-bits oxm_mask is equivalent to omitting the OXM TLV entirely. An all-one-bits oxm_mask
    is equivalent to specifying 0 for oxm_hasmask and omitting oxm_mask.

This patch fixes to compare OFPMatch ignoring fields that masks are all zero bits.

Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
sw test tool: Correct the comparison method to treat matches as the set

OF 1.3.3 spec (3 Glossary) says:

    Flow Entry: an element in a flow table used to match and process packets. It contains a set of
    match fields for matching packets, a priority for matching precedence, a set of counters to track
    packets, and a set of instructions to apply (see 5.2).

According to OF spec, the match fields are treated as the set.
This means that the order of matches which flow_stats message returns is inconsistant.
This patch corrects the comparison method of matches by sorting in a particular order before comparison.

Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
sw test tool: Improve difference analysis of packets

Using difflib instead of an original method.

Signed-off-by: WATANABE Fumitaka <watanabe.fumitaka1@gmail.com>
Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>
sw test tool: Improve difference analysis of FlowStats

Using difflib instead of an original method.

Signed-off-by: WATANABE Fumitaka <watanabe.fumitaka1@gmail.com>
Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>
sw test tool: Improve difference analysis of MeterStats

Using difflib instead of an original method.

Signed-off-by: WATANABE Fumitaka <watanabe.fumitaka1@gmail.com>
Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>