classes/populate_sdk_ext: sstate filtering fixes
A couple of fixes for the recent sstate filtering implemented in OE-Core
revision
4b7b48fcb9b39fccf8222650c2608325df2a4507:
* We shouldn't be deleting the downloads directory here, since it
contains the uninative tarball that we will need
* TMPDIR might not be named "tmp" - in OE-Core the default is tmp-glibc
so use the actual name of TMPDIR here instead.
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
