Merge branch 'rs/fix-unlink-unix-socket'

The unix-domain socket used by the sample credential cache daemon
tried to unlink an existing stale one at a wrong path, if the path
to the socket was given as an overlong path that does not fit in
sun_path member of the sockaddr_un structure.

* rs/fix-unlink-unix-socket:
  unix-socket: remove stale socket before calling chdir()