Update Order5_Type1.mo

It seems reasonable to comment out "der(delta) = 0;" in the initial equation of Order5_Type1 to alleviate the over-specified condition.

Fixes OpenIPSL#346

Author: gkhalley

OpenIPSL/Electrical/Machines/PSAT/Order5_Type1.mo

@@ -23,7 +23,6 @@ protected
   parameter Types.PerUnit e1d0=vd0 + ra*id0 - x1q*iq0 "Initialization*";
   parameter Types.PerUnit e2d0=vd0 + ra*id0 - x1q*iq0 "Initialization";
 initial equation
-  der(delta) = 0;
   der(e1q) = 0;
   der(e1d) = 0;
   der(e2d) = 0;