Fixed interpolation in jenkins_smtp custom state

Change-Id: Ie108bbdb841d3ebd2ddf69cb3256420e3e67404d
diff --git a/_states/jenkins_smtp.py b/_states/jenkins_smtp.py
index b3029b7..530eea2 100644
--- a/_states/jenkins_smtp.py
+++ b/_states/jenkins_smtp.py
@@ -12,7 +12,7 @@
        desc.getSmtpPort().equals("${port}") &&
        desc.getUseSsl() == ${ssl} &&
        desc.getCharset().equals("${charset}") &&
-       (!{reply_to_exists} || desc.getReplyAddress().equals("${reply_to}"))){
+       (!${reply_to_exists} || desc.getReplyAddress().equals("${reply_to}"))){
             result = "EXISTS"
     }else{
         desc.setSmtpAuth("${username}", "${password}")