Allocate memory for output command list handle

Allocate memory for output command list handle

'vc_get_system_command_list()' should return system command list with memory for handle for this
list. However previous code does not allocate memory.

This patch allocates new memory for output command list handle. System commands would be included
this new handle.
And also, this patch fixes the description of 'vc_get_system_command_list()' to deallocate memory
using 'vc_cmd_list_destroy()'.

Change-Id: Ie9d474d2115681b27c7f51f4da3f5487e7109eca
Signed-off-by: Suyeon Hwang <stom.hwang@samsung.com>