Destroy connection if the server does not support SSL

[lbguilherme]

Fix #2907 by removing the delay of ending the connection normally, as this is an error condition.

[brianc]

Thanks for this PR! I really appreciate it. Would it be possible to include a test? With github issues like #2907 sometimes I just make a file here with the issue number and you can basically copy/paste the code that's supposed to cleanly exit into the file...if the file never exits the test is considered a failure so it'd be a quick way to create a test for this in the future. If you don't want to run the full test suite locally you can run any individual file in the suite with node packages/pg/test/integration/gh-issues/2907-tests.js for example. pg was written before any of the now popular node test frameworks existed so the tests are basically each file is a self-contained script which must exit with 0 or the test suite is a fail, so its easy to just run one test (or file full of tests) at a time.