libutils: give BasicHashtableImpl a virtual destructor

Change-Id: I4ec590b060d732af5fe525670becbe778684247b
diff --git a/include/utils/BasicHashtable.h b/include/utils/BasicHashtable.h
index 7a6c96c..c235d62 100644
--- a/include/utils/BasicHashtable.h
+++ b/include/utils/BasicHashtable.h
@@ -52,6 +52,7 @@
     BasicHashtableImpl(size_t entrySize, bool hasTrivialDestructor,
             size_t minimumInitialCapacity, float loadFactor);
     BasicHashtableImpl(const BasicHashtableImpl& other);
+    virtual ~BasicHashtableImpl();
 
     void dispose();