Calling the base class constructor from the derived class' initializer list. This matches DenseMap's behavior, and silences some warnings.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188528 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/DenseMap.h

@@ -713,13 +713,13 @@ public:
     init(NumInitBuckets);
   }
 
-  SmallDenseMap(const SmallDenseMap &other) {
+  SmallDenseMap(const SmallDenseMap &other) : BaseT() {
     init(0);
     copyFrom(other);
   }
 
 #if LLVM_HAS_RVALUE_REFERENCES
-  SmallDenseMap(SmallDenseMap &&other) {
+  SmallDenseMap(SmallDenseMap &&other) : BaseT() {
     init(0);
     swap(other);
   }