It is preferred to use `[ "$FOO" ] || ...` instead of
`[ -z "$FOO" ] && ...` as the latter leaves $? set to 1.
(From OE-Core rev: d76c68505c36dbf383a989f3c2458abc765e2c19)
Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>