Changes

testenv: requirements: find programs in /usr/sbin

Fix that testenv complains about a missing setcap program, if it is in
/usr/sbin/setcap and /usr/sbin is not in PATH as it is the case with
Debian. We actually run setcap with sudo when it is needed, and in that
case /usr/sbin gets added to PATH in Debian.

Fix for:
  [testenv] Missing program: setcap

Change-Id: Ibbccba013ac38415ef46467f97bef846b848cf39