Switch all uses of LLVM_OVERRIDE to just use 'override' directly.

llvm-svn: 202621
diff --git a/llvm/lib/Support/DataStream.cpp b/llvm/lib/Support/DataStream.cpp
index 0bd0c68..d02b83c 100644
--- a/llvm/lib/Support/DataStream.cpp
+++ b/llvm/lib/Support/DataStream.cpp
@@ -58,7 +58,7 @@
   virtual ~DataFileStreamer() {
     close(Fd);
   }
-  virtual size_t GetBytes(unsigned char *buf, size_t len) LLVM_OVERRIDE {
+  virtual size_t GetBytes(unsigned char *buf, size_t len) override {
     NumStreamFetches++;
     return read(Fd, buf, len);
   }