[2726] Remove unnecessary template parameters

They are not needed, as it makes no sense to call constructor with
different template parameter than one of the class being constructed.
This also confused some versions of cppcheck and it thought there's no
constructor available.

src/lib/dns/message.h

@@ -98,10 +98,10 @@ struct SectionIteratorImpl;
 template <typename T>
 class SectionIterator : public std::iterator<std::input_iterator_tag, T> {
 public:
-    SectionIterator<T>() : impl_(NULL) {}
-    SectionIterator<T>(const SectionIteratorImpl<T>& impl);
-    ~SectionIterator<T>();
-    SectionIterator<T>(const SectionIterator<T>& source);
+    SectionIterator() : impl_(NULL) {}
+    SectionIterator(const SectionIteratorImpl<T>& impl);
+    ~SectionIterator();
+    SectionIterator(const SectionIterator<T>& source);
     void operator=(const SectionIterator<T>& source);
     SectionIterator<T>& operator++();
     SectionIterator<T> operator++(int);