[Support] Fix lifetime of file descriptors when using MemoryBuffer.

Clients of MemoryBuffer::getOpenFile expect it not to take ownership of the file
descriptor passed in. So don't.

llvm-svn: 176995
diff --git a/llvm/lib/Support/MemoryBuffer.cpp b/llvm/lib/Support/MemoryBuffer.cpp
index 1c354be..8042237 100644
--- a/llvm/lib/Support/MemoryBuffer.cpp
+++ b/llvm/lib/Support/MemoryBuffer.cpp
@@ -206,7 +206,7 @@
 public:
   MemoryBufferMMapFile(bool RequiresNullTerminator, int FD, uint64_t Len,
                        uint64_t Offset, error_code EC)
-      : MFR(FD, sys::fs::mapped_file_region::readonly,
+      : MFR(FD, false, sys::fs::mapped_file_region::readonly,
             getLegalMapSize(Len, Offset), getLegalMapOffset(Offset), EC) {
     if (!EC) {
       const char *Start = getStart(Len, Offset);
@@ -281,6 +281,7 @@
 
   error_code ret = getOpenFile(FD, Filename, result, FileSize, FileSize,
                                0, RequiresNullTerminator);
+  close(FD);
   return ret;
 }