Attempt to get EC_POINT from the current key first
Attempt to get EC_POINT from the current key first

This commit provides a cleaner implementation of #210.
An additional discussion is available in #209.

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