wic: Check for the existence/correctness of build artifacts
If a user uses the -e option and specifies a machine that hasn't been
built or uses the wrong .wks script for the build artifacts pointed to
by the current machine, we should point that out for obvious cases.
(From OE-Core master rev:
a5b9ccadc0603c70c65f74fa386995c585a951db)
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
