Ensure that in-memory buffer created serialisers have right version

* When flattening a log m_SerVer would be uninitialised which mean that
  if it was less than 0x32 we'd start aligning buffers when we shouldn't
  have.

renderdoc/serialise/serialiser.cpp

@@ -461,6 +461,8 @@ Serialiser::Serialiser(size_t length, const byte *memoryBuf, bool fileheader)
     m_CurrentBufferSize = (size_t)m_BufferSize;
     m_BufferHead = m_Buffer = AllocAlignedBuffer(m_CurrentBufferSize);
 
+    m_SerVer = SERIALISE_VERSION;
+
     memcpy(m_Buffer, memoryBuf, m_CurrentBufferSize);
     return;
   }