support: Fix typo in xgetsockname error message

The error message in xgetsockname was incorrectly referring to a
different function.  This commit fixes that.

Suggested-by: Arjun Shankar <arjun@redhat.com>
Signed-off-by: Avinal Kumar <avinal.xlvii@gmail.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>