ceph: valgrind trumps coverage when picking a flavor
ceph: valgrind trumps coverage when picking a flavor

valgrind will crash if we don't use notcmalloc; coverage will silently
fail to collect coverage info.

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