Fix a couple cast errors

src/deoptimizer.cc

Index: src/deoptimizer.cc
diff --git a/src/deoptimizer.cc b/src/deoptimizer.cc
index dd70baaa16575e9c595af2bd511e2cb0a2871096..185ff92242b384ed3432fc8ef7a0dfbb4d331ed7 100644
--- a/src/deoptimizer.cc
+++ b/src/deoptimizer.cc
@@ -309,9 +309,9 @@ void Deoptimizer::TearDown() {
 }
 
 
-unsigned Deoptimizer::GetOutputInfo(DeoptimizationOutputData* data,
-                                    unsigned id,
-                                    SharedFunctionInfo* shared) {
+int Deoptimizer::GetOutputInfo(DeoptimizationOutputData* data,
+                               unsigned id,
+                               SharedFunctionInfo* shared) {
   // TODO(kasperl): For now, we do a simple linear search for the PC
   // offset associated with the given node id. This should probably be
   // changed to a binary search.