task/kernel: simplify filter/lambda for py3
task/kernel: simplify filter/lambda for py3

Signed-off-by: Kyr Shatskyy <82d0c7561ff7e9a20a19db22e8fb5b2adaa3d71e@suse.com>

ktdreyer/teuthology,SUSE/teuthology,dmick/teuthology,dmick/teuthology,SUSE/teuthology,SUSE/teuthology,ceph/teuthology,dmick/teuthology,ceph/teuthology,ktdreyer/teuthology