honor smtp_host option in koji-gc (jflorian)

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1367945

Merges: #136

util/koji-gc

@@ -433,9 +433,8 @@ refer to the document linked above for instructions."""
         if options.debug:
             print "Sending warning notice to %s" % msg['To']
         s = smtplib.SMTP(options.smtp_host)
-        s.connect()
         s.sendmail(msg['From'], msg['To'], msg.as_string())
-        s.close()
+        s.quit()
 
 
 def main(args):