[LLD] [COFF] Fix -Wmissing-field-initializers warnings. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@374873 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/COFF/SymbolTable.cpp b/COFF/SymbolTable.cpp
index 61df04e..2d971a0 100644
--- a/COFF/SymbolTable.cpp
+++ b/COFF/SymbolTable.cpp
@@ -157,7 +157,7 @@
       if (fileLine)
         locations.push_back({sym, *fileLine});
       else if (sym)
-        locations.push_back({sym});
+        locations.push_back({sym, {"", 0}});
     }
   }