Fix POD for bug 471620, r=dkl

Bugzilla/WebService/Constants.pm

@@ -103,6 +103,7 @@ use constant WS_ERROR_CODE => {
     account_creation_disabled   => 501,
     account_creation_restricted => 501,
     password_too_short    => 502,
+    # Error 503 password_too_long no longer exists.
     invalid_username      => 504,
     # This is from strict_isolation, but it also basically means 
     # "invalid user."

Bugzilla/WebService/User.pm

@@ -419,10 +419,13 @@ the function may also throw:
 The password specified is too short. (Usually, this means the
 password is under three characters.)
 
-=item 503 (Password Too Long)
+=back
+
+=item B<History>
+
+=over
 
-The password specified is too long. (Usually, this means the
-password is over ten characters.)
+=item Error 503 (Password Too Long) removed in Bugzilla B<3.6>.
 
 =back