(maint) update preinst for redhat to check for 2.x if upgrading
(maint) update preinst for redhat to check for 2.x if upgrading

This should fix the issue where we attempted to tar a nonexistent directory in
preinst when upgrading from 3.0.0 -> 3.0.x

waynr/puppetdb,kbarber/puppetdb,mullr/puppetdb,puppetlabs/puppetdb,waynr/puppetdb,kbrezina/puppetdb,puppetlabs/puppetdb,highb/puppetdb,kbrezina/puppetdb,rbrw/puppetdb,kbrezina/puppetdb,kbrezina/puppetdb,senior/puppetdb,rbrw/puppetdb,ajroetker/puppetdb,puppetlabs/puppetdb,waynr/puppetdb,grimradical/puppetdb,senior/puppetdb,puppetlabs/puppetdb,grimradical/puppetdb,senior/puppetdb,highb/puppetdb,rbrw/puppetdb,rbrw/puppetdb,wkalt/puppetdb,highb/puppetdb,senior/puppetdb,ajroetker/puppetdb,mullr/puppetdb,highb/puppetdb,mullr/puppetdb,ajroetker/puppetdb,mullr/puppetdb,kbarber/puppetdb,rbrw/puppetdb,wkalt/puppetdb,grimradical/puppetdb,kbarber/puppetdb,wkalt/puppetdb,mullr/puppetdb,waynr/puppetdb,ajroetker/puppetdb,kbarber/puppetdb,puppetlabs/puppetdb,wkalt/puppetdb,grimradical/puppetdb