Bug 531500: Allow the mailer_before_send hook to modify the arguments passed to Email::Send

Bugzilla/Hook.pm

@@ -482,6 +482,9 @@ Params:
 
 =item C<email> - The C<Email::MIME> object that's about to be sent.
 
+=item C<mailer_args> - An arrayref that's passed as C<mailer_args> to
+L<Email::Send/new>.
+
 =back
 
 =head2 object_before_create

Bugzilla/Mailer.pm

@@ -171,7 +171,8 @@ sub MessageToMTA {
                     Debug => Bugzilla->params->{'smtp_debug'};
     }
 
-    Bugzilla::Hook::process('mailer_before_send', { email => $email });
+    Bugzilla::Hook::process('mailer_before_send', 
+                            { email => $email, mailer_args => \@args });
 
     if ($method eq "Test") {
         my $filename = bz_locations()->{'datadir'} . '/mailer.testfile';