(PE-962) remove unnecessary extra index on primary key
(PE-962) remove unnecessary extra index on primary key

Because the `node` column of the new `latest_reports` table is already marked as the `PRIMARY KEY`, we don't need to explicitly create an index on it.

shrug/puppetdb,kbrezina/puppetdb,grimradical/puppetdb,rbrw/puppetdb,jantman/puppetdb,puppetlabs/puppetdb,rbrw/puppetdb,puppetlabs/puppetdb,johnduarte/puppetdb,puppetlabs/puppetdb,cprice404/puppetdb,johnduarte/puppetdb,senior/puppetdb,mullr/puppetdb,senior/puppetdb,shrug/puppetdb,wkalt/puppetdb,waynr/puppetdb,rbrw/puppetdb,jantman/puppetdb,waynr/puppetdb,ajroetker/puppetdb,grimradical/puppetdb,ajroetker/puppetdb,mullr/puppetdb,kbarber/puppetdb,kbrezina/puppetdb,kbrezina/puppetdb,shrug/puppetdb,highb/puppetdb,kbarber/puppetdb,shrug/puppetdb,cprice404/puppetdb,mullr/puppetdb,wkalt/puppetdb,highb/puppetdb,puppetlabs/puppetdb,waynr/puppetdb,puppetlabs/puppetdb,wkalt/puppetdb,senior/puppetdb,ajroetker/puppetdb,kbarber/puppetdb,wkalt/puppetdb,mullr/puppetdb,grimradical/puppetdb,grimradical/puppetdb,johnduarte/puppetdb,senior/puppetdb,johnduarte/puppetdb,ajroetker/puppetdb,cprice404/puppetdb,waynr/puppetdb,highb/puppetdb,rbrw/puppetdb,kbarber/puppetdb,jantman/puppetdb,kbrezina/puppetdb,mullr/puppetdb,highb/puppetdb,rbrw/puppetdb