Really fix the missing header :-(

llvm-svn: 184355
diff --git a/llvm/tools/llvm-ar/Archive.h b/llvm/tools/llvm-ar/Archive.h
index 6c7575a..0fe72f4 100644
--- a/llvm/tools/llvm-ar/Archive.h
+++ b/llvm/tools/llvm-ar/Archive.h
@@ -23,7 +23,7 @@
 #include "llvm/Support/TimeValue.h"
 #include <map>
 #include <set>
-#include <vector.h>
+#include <vector>
 
 namespace llvm {
   class MemoryBuffer;