kernel: fix 'sha1: distro' vs per role configs
kernel: fix 'sha1: distro' vs per role configs

We may want to setup different kernels for different roles (as long as
all roles on the same node agree on their choice), so returning as soon
as 'distro' is seen is not right.  Also, no need to use find() as
'distro' is always an exact match.

Signed-off-by: Ilya Dryomov <152d4c5bebf13a5b809d42b4d789cf9d887e6698@redhat.com>

dmick/teuthology,ceph/teuthology,ktdreyer/teuthology,SUSE/teuthology,dmick/teuthology,t-miyamae/teuthology,caibo2014/teuthology,zhouyuan/teuthology,yghannam/teuthology,dreamhost/teuthology,t-miyamae/teuthology,ktdreyer/teuthology,tchaikov/teuthology,SUSE/teuthology,ivotron/teuthology,michaelsevilla/teuthology,dmick/teuthology,zhouyuan/teuthology,yghannam/teuthology,michaelsevilla/teuthology,SUSE/teuthology,dreamhost/teuthology,robbat2/teuthology,caibo2014/teuthology,ceph/teuthology,ivotron/teuthology,tchaikov/teuthology,robbat2/teuthology