Add error handling for test e-mail.

Review Request #8924 — Created May 7, 2017 and submitted — Latest diff uploaded

Information

Review Board
release-2.5.x
20e7b81...

Reviewers

When updating e-mail server settings having "Send a test e-mail after
saving" selected it is helpful to get some feedback when the e-mail
could not be sent. With this change an error message is displayed and
the exception logged.

Configured e-mail server (smtp.gmail.com) with wrong username, wrong
password, no TLS, misspelled server and observed error message and
exception in log for every case. Using an invalid port resulted in a
timeout.