Fixing logic of VmaDefragmentationAlgorithm_Fast::PostprocessMetadata broken by #201

Closes #202

include/vk_mem_alloc.h

diff --git a/include/vk_mem_alloc.h b/include/vk_mem_alloc.h
index 4463be8..11b7840 100644
--- a/include/vk_mem_alloc.h
+++ b/include/vk_mem_alloc.h
@@ -13071,9 +13071,9 @@
                         freeSize, // size

                         VMA_NULL, // hAllocation

                         VMA_SUBALLOCATION_TYPE_FREE };

+                    VmaSuballocationList::iterator precedingFreeIt = pMetadata->m_Suballocations.insert(it, suballoc);

                     if(freeSize >= VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER)

                     {

-                        VmaSuballocationList::iterator precedingFreeIt = pMetadata->m_Suballocations.insert(it, suballoc);

                         pMetadata->m_FreeSuballocationsBySize.push_back(precedingFreeIt);

                     }

                 }

@@ -13093,9 +13093,9 @@
                     VMA_NULL, // hAllocation

                     VMA_SUBALLOCATION_TYPE_FREE };

                 VMA_ASSERT(it == pMetadata->m_Suballocations.end());

+                VmaSuballocationList::iterator trailingFreeIt = pMetadata->m_Suballocations.insert(it, suballoc);

                 if(freeSize > VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER)

                 {

-                    VmaSuballocationList::iterator trailingFreeIt = pMetadata->m_Suballocations.insert(it, suballoc);

                     pMetadata->m_FreeSuballocationsBySize.push_back(trailingFreeIt);

                 }

             }