utility-tasks: Set T to alternate location during do_clean
There is a race where do_clean tries to clean WORKDIR but there are logfiles
written into ${T} by bitbake and this can lead to exceptions due to open files.
The easiest solution is to redirect T to a different location for the do_clean
task, hence avoiding the errors and also allowing the logfiles to be visible
somewhere. ${LOG_DIR} seems an appropriate place for this.
[YOCTO #2846]
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
