Support/FileSystem: Fix copy_file implementation to use toNullTerminatedStringRef
instead of toStringRef. The file system APIs need c strings.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120601 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Unix/PathV2.inc b/lib/Support/Unix/PathV2.inc
index d12cd16..0fa4b87 100644
--- a/lib/Support/Unix/PathV2.inc
+++ b/lib/Support/Unix/PathV2.inc
@@ -71,8 +71,8 @@
  // Get arguments.
   SmallString<128> from_storage;
   SmallString<128> to_storage;
-  StringRef f = from.toStringRef(from_storage);
-  StringRef t = to.toStringRef(to_storage);
+  StringRef f = from.toNullTerminatedStringRef(from_storage);
+  StringRef t = to.toNullTerminatedStringRef(to_storage);
 
   const size_t buf_sz = 32768;
   char buffer[buf_sz];