Revert "Add engine ref setup in load_privkey() (#181)"
Revert "Add engine ref setup in load_privkey() (#181)"

This reverts commit aa2349110191818f003d940cb754e437baf073f5.

mtrojnar/libp11,dengert/libp11,mtrojnar/libp11,dengert/libp11,mouse07410/libp11,mouse07410/libp11,OpenSC/libp11,OpenSC/libp11