sk-unix: Fix memory leak on error path

Dynamically allocated @name doesn't release
if error happened.

 | ** CID 129898:    (RESOURCE_LEAK)
 | /sk-unix.c: 505 in unix_process_name()
 | /sk-unix.c: 509 in unix_process_name()
 | /sk-unix.c: 519 in unix_process_name()

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>