Clean up VariableSizeBlobs on Slice destruction.
Clean up VariableSizeBlobs on Slice destruction.

danluu/BitFunnel,BitFunnel/BitFunnel,danluu/BitFunnel,danluu/BitFunnel,BitFunnel/BitFunnel,BitFunnel/BitFunnel,BitFunnel/BitFunnel,BitFunnel/BitFunnel,danluu/BitFunnel,danluu/BitFunnel,danluu/BitFunnel,BitFunnel/BitFunnel