Fixed a warning in BlockMetadata_TLSF::WriteAllocationInfoToJson

Fixes #67 - thanks @ttcvetkov
diff --git a/src/D3D12MemAlloc.cpp b/src/D3D12MemAlloc.cpp
index 4b85b11..ecb1330 100644
--- a/src/D3D12MemAlloc.cpp
+++ b/src/D3D12MemAlloc.cpp
@@ -5030,7 +5030,8 @@
     }

     D3D12MA_ASSERT(i == 0);

 

-    PrintDetailedMap_Begin(json, GetSumFreeSize(), GetAllocationCount(), m_BlocksFreeCount + static_cast<bool>(m_NullBlock->size));

+    PrintDetailedMap_Begin(json, GetSumFreeSize(), GetAllocationCount(), m_BlocksFreeCount +

+        (m_NullBlock->size > 0 ? 1 : 0));

     for (; i < blockCount; ++i)

     {

         Block* block = blockList[i];