wic: Make exec_native_command() fail if a command isn't found
Because exec_cmd() return values can in certain cases be non-zero yet
non-fatal, we don't want to automatically make them fatal (though
there should at least be a warning in such cases, which this patch
also does); non-zero return values are definitely fatal however if
they mean that a native command wasn't found, so have
exec_native_cmd() check the return value of exec_cmd() for that case,
and bail out if so.
[YOCTO #5835]
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Saul Wold <sgw@linux.intel.com>
