Remove unused variable

Fixes #67
diff --git a/src/vk_mem_alloc.h b/src/vk_mem_alloc.h
index cf03d10..69fe6ba 100644
--- a/src/vk_mem_alloc.h
+++ b/src/vk_mem_alloc.h
@@ -12447,7 +12447,6 @@
     const VkMemoryPropertyFlags memPropFlags =

         m_hAllocator->m_MemProps.memoryTypes[m_MemoryTypeIndex].propertyFlags;

     const bool isHostVisible = (memPropFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0;

-    const bool isHostCoherent = (memPropFlags & VK_MEMORY_PROPERTY_HOST_COHERENT_BIT) != 0;

 

     const bool canDefragmentOnCpu = maxCpuBytesToMove > 0 && maxCpuAllocationsToMove > 0 &&

         isHostVisible;