Small const-correctness fix


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50723 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvmc2/Action.cpp b/tools/llvmc2/Action.cpp
index 82a1e0c..8d34910 100644
--- a/tools/llvmc2/Action.cpp
+++ b/tools/llvmc2/Action.cpp
@@ -48,7 +48,7 @@
   }
 }
 
-int llvmcc::Action::Execute() {
+int llvmcc::Action::Execute() const {
   if (VerboseMode) {
     std::cerr << Command_ << " ";
     std::for_each(Args_.begin(), Args_.end(), print_string);