Do not explicitly call strerror(errnum) when logging

[mykaul]

For example, instead of:

        gf_msg_debug(this->name, 0, "unlink of %s on %s failed (%s)",
                     local->loc2.path, prev->name, strerror(op_errno));

Use:

        gf_msg_debug(this->name, op_errno, "unlink of %s on %s failed",
                     local->loc2.path, prev->name);

As I believe, that errno is propagated all the way in the logging to finally become the footer:

    /* generate footer */
    if (errnum) {
        ret = gf_asprintf(&footer, " [%s]\n", strerror(errnum));

[stale]

Thank you for your contributions.
Noticed that this issue is not having any activity in last ~6 months! We are marking this issue as stale because it has not had recent activity.
It will be closed in 2 weeks if no one responds with a comment here.

[mykaul]

unstale please