[Bugfix] Add correct PlainPasswd constructor to avoid vncpasswd crash.

Reference: https://bugzilla.redhat.com/show_bug.cgi?id=499401


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@3812 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/common/rfb/Password.cxx b/common/rfb/Password.cxx
index 9127862..240c9d4 100644
--- a/common/rfb/Password.cxx
+++ b/common/rfb/Password.cxx
@@ -38,6 +38,9 @@
 PlainPasswd::PlainPasswd(char* pwd) : CharArray(pwd) {
 }
 
+PlainPasswd::PlainPasswd(int len) : CharArray(len) {
+}
+
 PlainPasswd::PlainPasswd(const ObfuscatedPasswd& obfPwd) : CharArray(9) {
   if (obfPwd.length < 8)
     throw rdr::Exception("bad obfuscated password length");