Silence some -Asserts uninitialized variable warnings.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109956 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/WinCOFFObjectWriter.cpp b/lib/MC/WinCOFFObjectWriter.cpp
index a4bbc53..4fb806e 100644
--- a/lib/MC/WinCOFFObjectWriter.cpp
+++ b/lib/MC/WinCOFFObjectWriter.cpp
@@ -579,6 +579,7 @@
 
   COFFRelocation Reloc;
 
+  Reloc.Data.SymbolTableIndex = 0;
   Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
   Reloc.Symb = coff_symbol;