Duplication reported by PMD tool

[KFilipek]

ISSUE: Duplication reported by PMD tool

Environment Information

Name	Version
pmemkv version(s)	54f2660
libpmemobj-cpp version(s)	N/A
PMDK (libpmem/libpmemobj) version(s)	N/A
OS(es) version(s)	N/A
kernel version(s)	N/A
compiler, libraries, packaging and other related tools version(s)	N/A

Please provide a reproduction of the bug:

./bin/run.sh cpd --minimum-tokens 100 --files ~/Development/work/pmemkv/src/ --language cpp

Details

I removed API related duplications.

Found a 22 line (172 tokens) duplication in the following files: 
Starting at line 1918 of /home/kfilipek/Development/work/pmemkv/src/engines-experimental/stree/persistent_b_tree.h
Starting at line 1960 of /home/kfilipek/Development/work/pmemkv/src/engines-experimental/stree/persistent_b_tree.h

b_tree_base<Key, T, Compare, degree>::split_leaf_node(pool_base &pop,
						      leaf_pptr &split_leaf, K &&key,
						      M &&obj)
{
	assert(split_leaf->full());

	leaf_pptr node;
	std::pair<iterator, bool> result(nullptr, false);
	auto middle = split_leaf->begin() + split_leaf->size() / 2;
	bool less = compare(std::forward<K>(key), middle->first);
	// move second half into node and insert new element where needed
	pmem::obj::transaction::run(pop, [&] {
		node = allocate_leaf();
		node->move(pop, split_leaf, compare);
		/* insert entry(key, obj) into needed half */
		if (less) {
			result = internal_insert(split_leaf, std::forward<K>(key),
						 std::forward<M>(obj));
		} else {
			result = internal_insert(node, std::forward<K>(key),
						 std::forward<M>(obj));
		}