Log: libcrmcommon: Drop crm_perror() in io.c

The only callers of pcmk__sync_directory() are in cib_file.c.

We lose logging to stderr for CLI tools that use the cib_file interface.
But CLI tools have verbose flags, and it doesn't seem worth passing a
pcmk__output_t down the call chain.

Ref T172

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>