address review comments for 0.0.9 upgrade

* remove code for submodules as they aren't used by obfs4proxy
* clean repo before zipping source tree
* allow CI failure for verification (new releases can only be verified
  after uploaded)
3 jobs for <span class="ref-name">obfsproxy-0.0.9</span> in 8 minutes and 56 seconds (queued for 6 minutes and 8 seconds)
Status Job ID Name Coverage
  Build
passed #3033
build

00:02:02

 
  Test
passed #3057
allowed to fail
test

00:06:54

failed #3034
allowed to fail
test

00:06:52