refs ZEN-3890 add an objectExists router method reviewed by epowell


git-svn-id: http://dev.zenoss.com/svnint/trunk/core@74211 f5df01ce-0320-0410-9ed9-ddcd13c732cc
Fixes ZEN-7041 panic exit when presented with bad zenbatchload loaders.Reviewed by Ian McCracken

git-svn-id: http://dev.zenoss.com/svnint/trunk/core@74216 f5df01ce-0320-0410-9ed9-ddcd13c732cc