Add preconditions to db storage functions
Add preconditions to db storage functions

haus/puppetdb,kbarber/puppetdb,shrug/puppetdb,kbrezina/puppetdb,ajroetker/puppetdb,nfagerlund/puppetdb,senior/puppetdb,senior/puppetdb,melissa/puppetdb,jantman/puppetdb,stahnma/puppetdb,rbrw/puppetdb,cprice404/puppetdb,senior/puppetdb,cprice404/puppetdb,highb/puppetdb,mullr/puppetdb,github/puppetlabs-puppetdb,kbarber/puppetdb,jantman/puppetdb,rbrw/puppetdb,waynr/puppetdb,kbrezina/puppetdb,puppetlabs/puppetdb,wkalt/puppetdb,highb/puppetdb,wkalt/puppetdb,mullr/puppetdb,rbrw/puppetdb,melissa/puppetdb,haus/puppetdb,mullr/puppetdb,mullr/puppetdb,johnduarte/puppetdb,rbrw/puppetdb,wkalt/puppetdb,kbrezina/puppetdb,mullr/puppetdb,waynr/puppetdb,grimradical/puppetdb,shrug/puppetdb,waynr/puppetdb,waynr/puppetdb,haus/puppetdb,jantman/puppetdb,highb/puppetdb,grimradical/puppetdb,shrug/puppetdb,github/puppetlabs-puppetdb,kbarber/puppetdb,melissa/puppetdb,highb/puppetdb,puppetlabs/puppetdb,rbrw/puppetdb,kbarber/puppetdb,wkalt/puppetdb,puppetlabs/puppetdb,puppetlabs/puppetdb,johnduarte/puppetdb,johnduarte/puppetdb,ajroetker/puppetdb,github/puppetlabs-puppetdb,stahnma/puppetdb,puppetlabs/puppetdb,ajroetker/puppetdb,ajroetker/puppetdb,johnduarte/puppetdb,stahnma/puppetdb,shrug/puppetdb,nfagerlund/puppetdb,grimradical/puppetdb,kbrezina/puppetdb,nfagerlund/puppetdb,senior/puppetdb,grimradical/puppetdb,cprice404/puppetdb