tools: Adds support for SMTP with STARTTLS to notifier

Adds support for sending emails using SMTP with STARTTLS.

Change-Id: I751a0db149cbd217728c036a65f7fadc6da4cdf9
Bug-Url: https://bugzilla.redhat.com/1020920
Signed-off-by: Martin Perina <mperina@redhat.com>