devtool: show proper error when extracting source for recipes with disabled unpack task
If you try to use "devtool modify -x" or "devtool extract" on a recipe
where do_unpack has been set as noexec (e.g. glibc-locale), then we get
an error because the expected source wasn't ever unpacked. Do a check up
front for noexec being set on do_unpack and error out with a reasonable
message if that's the case.
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
