Display security state when asking for password

Indicate to the user how secure the transport channel is so they
can avoid entering their password for untrusted sites.
diff --git a/common/rfb/CSecurityVncAuth.cxx b/common/rfb/CSecurityVncAuth.cxx
index f44e56e..46463e0 100644
--- a/common/rfb/CSecurityVncAuth.cxx
+++ b/common/rfb/CSecurityVncAuth.cxx
@@ -49,7 +49,7 @@
   rdr::U8 challenge[vncAuthChallengeSize];
   is->readBytes(challenge, vncAuthChallengeSize);
   PlainPasswd passwd;
-  (CSecurity::upg)->getUserPasswd(0, &passwd.buf);
+  (CSecurity::upg)->getUserPasswd(cc->isSecure(), 0, &passwd.buf);
 
   // Calculate the correct response
   rdr::U8 key[8];