Add check for Entrypoint configuration to docker backend
Add check for Entrypoint configuration to docker backend

hfm/specinfra,chef-partners/specinfra-cisco,miketheman/specinfra,k0kubun/specinfra,uroesch/specinfra,glenux/contrib-specinfra,pfaffle/specinfra,edolnx/specinfra,verisign/specinfra,electrical/specinfra,elibus/specinfra,mizzy/specinfra,bodgit/specinfra,sean-horn/specinfra,serverspec/specinfra,minimum2scp/specinfra,winebarrel/specinfra,tacahilo/specinfra,higanworks/specinfra,stefanhorning/specinfra,ihassin/specinfra,chinthakagodawita/specinfra,RoboticCheese/specinfra,seroron/specinfra,sergueik/specinfra,chorrell/specinfra,nurse/specinfra,gh2k/specinfra,mactkg/specinfra