kernel: fix sha1
kernel: fix sha1

6f8910eca47c3d00643c77fb8a166357637e55eb inadvertantly started
using the ceph sha1 for the kernel.

Signed-off-by: Sage Weil <6dd34506bbd5e58221bbb3e4732d97c91f02277b@inktank.com>

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