* Support for custom SMTP hello string
Some MTAs insist that they be greeted with a fully qualified domain
name. The default provided by the net/smtp library, "HELLO localhost",
is not sufficient and will result in rejected messages.
This changeset adds a new configuration option that allows the
alertmanager to do its job in such an environment.
* Test SMTPHello parsing
Jose Donizetti
Steven Carvellas
ideaship
Carlos Alexandro Becker
Conor Broderick
Frederic Branczyk