"pcscd" wouldn't handle SIGTERM as it inherit ignoring this signal (and
others) from its parent shepherd; fork+exec-command restore signal
handling. Fixes <https://issues.guix.gnu.org/45202>.
* gnu/services/security-token.scm (pcscd)[start]: Use
fork+exec-command to start "pcscd".
Otherwise when pcscd doesn't terminate properly (ie. receive a SIGKILL),
it won't start again because of it's socket already existing.
* gnu/services/security-token.scm (pcscd-shepherd-service)[start]:
Remove existing socket file.
Fixes: <https://bugs.gnu.org/32478>.
* gnu/services/security-token.scm (pcscd-activation): Idempotently create the
/var/lib/pcsc symlink so that it does not fail when it already exists.
