Fixed that MailHandler raises an error when email has no subject header (#12396).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@10850 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/mail_handler.rb

@@ -124,6 +124,7 @@ class MailHandler < ActionMailer::Base
 
   def dispatch
     headers = [email.in_reply_to, email.references].flatten.compact
+    subject = email.subject.to_s
     if headers.detect {|h| h.to_s =~ MESSAGE_ID_RE}
       klass, object_id = $1, $2.to_i
       method_name = "receive_#{klass}_reply"
@@ -132,9 +133,9 @@ class MailHandler < ActionMailer::Base
       else
         # ignoring it
       end
-    elsif m = email.subject.match(ISSUE_REPLY_SUBJECT_RE)
+    elsif m = subject.match(ISSUE_REPLY_SUBJECT_RE)
       receive_issue_reply(m[1].to_i)
-    elsif m = email.subject.match(MESSAGE_REPLY_SUBJECT_RE)
+    elsif m = subject.match(MESSAGE_REPLY_SUBJECT_RE)
       receive_message_reply(m[1].to_i)
     else
       dispatch_to_default