[PDB] Add missing override to silence buildbots

llvm-svn: 325828
diff --git a/llvm/unittests/DebugInfo/PDB/PDBApiTest.cpp b/llvm/unittests/DebugInfo/PDB/PDBApiTest.cpp
index 9cf5143..ff49a9c 100644
--- a/llvm/unittests/DebugInfo/PDB/PDBApiTest.cpp
+++ b/llvm/unittests/DebugInfo/PDB/PDBApiTest.cpp
@@ -143,7 +143,7 @@
   }
   std::unique_ptr<IPDBEnumSymbols>
   findChildrenByAddr(PDB_SymType Type, StringRef Name, PDB_NameSearchFlags Flags,
-                     uint32_t Section, uint32_t Offset) const {
+                     uint32_t Section, uint32_t Offset) const override {
     return nullptr;
   }
   std::unique_ptr<IPDBEnumSymbols>