buildpackages: fix dates in spec file changelog
buildpackages: fix dates in spec file changelog

Eliminates the following warnings:

2018-03-03T06:56:01.948 DEBUG:teuthology.misc:warning: bogus date in %changelog: Tue Mar 10 2013 Gary Lowell <glowell@inktank.com> - 1-0
2018-03-03T06:56:01.948 DEBUG:teuthology.misc:warning: bogus date in %changelog: Tue Aug 27 2012 Gary Lowell <glowell@inktank.com> - 1-0

Signed-off-by: Nathan Cutler <f9d8c66a4e898e67db786769b5b347b640e1a9a6@suse.com>

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