llvm: fix leaks
llvm: fix leaks

Delete params and fix recounting on subgraph, so that
they will get properly destroyed.

Signed-off-by: Marek Chalupa <a05df156a69ad59faa9af9b666ef78009594c145@gmail.com>

mchalupa/dg,mchalupa/dg,mchalupa/dg,mchalupa/dg