BUG: 14412 Handle '0 builds' and '0 failed tests' cases properly. (by Igor)

git-svn-id: https://www.kitware.com/svn/CDash/trunk@3365 91079597-3006-4846-9bd3-4f3fb3d139a7
STYLE: 14413: Fix grammar in coverage manager (by Igor Murzov)

git-svn-id: https://www.kitware.com/svn/CDash/trunk@3366 91079597-3006-4846-9bd3-4f3fb3d139a7