When Hob is busy with generating data, exiting Hob is not allowed.
That should be reasonable because at that time the mouse cursor is not a pointer.
If users want to exit, they can click "Stop" first and then do exit.
That is also a walkaround for [Yocto #2142]
(Bitbake rev: ad7f6bf3c7c4c15d546781aaefdaf03f00193f7c)
Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>