This is merge request for bug fix release that fixes remove helloverify countermeasure was not effective in last release.
The root cause was that a line of edit was lost during the backporting process(https://github.com/xiaokangwang/dtls/commit/16e5cc8ce01c0262e4d945b7fe90eba4d7d58ce5)
X~X maybe we will need to repeat the test before actually merging in the future to reduce this kind of mistake.