scd: Serialize READER_TABLE access for PC/SC.
* scd/apdu.c (apdu_dev_list_start): Remove locking READER_TABLE_LOCK. Don't increment PCSC.COUNT here. (apdu_dev_list_finish): Don't decrement PCSC.COUNT here. (apdu_open_reader): Protect access with READER_TABLE_LOCK.
- GnuPG-bug-id: T5416
- Fixes-commit: 8d81fd7c01e8dfacc719ff190f8e364014e32fdf
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>