Fix Socks5 proxy tests
Fix Socks5 proxy tests

- reset net listener after each test
- actual expectations in net listener failure test

Signed-off-by: Nick Mahoney <37df72260815dd7c7e09de5254fe02d7d2694eb5@pivotal.io>

pivotal-cf-experimental/bosh-bootloader,niroyb/bosh-bootloader,niroyb/bosh-bootloader,pivotal-cf-experimental/bosh-bootloader