fix closure p2

fluid/fluid_problem_fem.c

@@ -5,7 +5,7 @@
 
 
 static int CLOSURE_TRIANGLE_P1[12] = {0,1,1,2,2,0,1,0,2,1,0,2};
-static int CLOSURE_TRIANGLE_P2[18] = {0,1,3,2,2,4,2,0,5,1,0,3,2,1,4,0,2,5};
+static int CLOSURE_TRIANGLE_P2[18] = {0,1,3,1,2,4,2,0,5,1,0,3,2,1,4,0,2,5};
 
 static double XI_TRIANGLE_P1[][D] = {
   {0.0,0.0},{1.0,0.0},{0.0,1.0}};