* scd/apdu.c (new_reader_slot): Acquire lock.
(open_ct_reader, open_pcsc_reader_direct, open_pcsc_reader_wrapped)
(open_ccid_reader, open_rapdu_reader): Release lock.
--
Fixes a test case of:
No libpcsclite1 installed.
Run gpg-agent
Run command "gpg-connect-agent learn /bye" with no card/token
Sometimes it fails: ERR 100663356 Not supported <SCD>
While it should be always: ERR 100663404 Card error <SCD>