tests.migrate_speed: Expand test cases with verifying speed.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
tests.migrate_speed: Adjustment for checking TestNAError.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Merge pull request #203 from yumingfei/migrate_set_get_speed

tests.migrate_set_get_speed: Expand testcases with verifying.