Changes

util: fix the functions "create_netns" and "setcap_netsys_admin".

This commit fixes 2 functions from util.py:
 - setcap_netsys_admin: removed "self" from the arguments.
 - create_netns: pass "run_dir" to Process and convert the arguments to
a list as the other methods in the file.

Change-Id: Ida4c6d6500be92b8d1f96e4e7a870e63bd329be9