Add missing initializer.

Author: dtarditi

MultiSource/Benchmarks/Olden/mst/main.c

@@ -85,7 +85,7 @@ static Vertex MyVertexList = NULL;
 
 static BlueReturn Do_all_BlueRule(Vertex inserted, int nproc, int pn) {
  future_cell_BlueReturn fcleft = { 0 };
- BlueReturn retright;
+ BlueReturn retright = { 0 };
 
  if (nproc > 1) {
  fcleft.value = Do_all_BlueRule(inserted,nproc/2,pn+nproc/2);