Add Binary flag to raw_fd_ostream constructor.

Document raw_fd_ostream's treatment of "-".


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59219 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/lto/LTOCodeGenerator.cpp b/tools/lto/LTOCodeGenerator.cpp
index 0474a88..e0e1f52 100644
--- a/tools/lto/LTOCodeGenerator.cpp
+++ b/tools/lto/LTOCodeGenerator.cpp
@@ -165,7 +165,7 @@
     // generate assembly code
     bool genResult = false;
     {
-      raw_fd_ostream asmFile(uniqueAsmPath.c_str(), errMsg);
+      raw_fd_ostream asmFile(uniqueAsmPath.c_str(), false, errMsg);
       if (!errMsg.empty())
         return NULL;
       genResult = this->generateAssemblyCode(asmFile, errMsg);