Properly close mapped files.

llvm-svn: 19863
diff --git a/llvm/lib/Bytecode/Archive/Archive.cpp b/llvm/lib/Bytecode/Archive/Archive.cpp
index 2d79bd6..aa2db41 100644
--- a/llvm/lib/Bytecode/Archive/Archive.cpp
+++ b/llvm/lib/Bytecode/Archive/Archive.cpp
@@ -143,7 +143,7 @@
 Archive::~Archive() {
   // Shutdown the file mapping
   if (mapfile) {
-    mapfile->unmap();
+    mapfile->close();
     delete mapfile;
   }
   // Delete any ModuleProviders and ArchiveMember's we've allocated as a result