Doesn't work with authenticated proxy

[David Yu]

Repro:

1. Setup a proxy such as squid
2. Configure proxy to require auth (username + password)
3. Configure Tomcat's catalina.properties with https.proxyHost, https.proxyPort, https.proxyUser, https.proxyPassword

Version: 1.3.5

The previous version would at least list the rooms, but would fail to send any messages to the rooms.

[David Yu]

Similar problem described here: https://jira.atlassian.com/browse/STASH-4013