add Chef::NodeMap#delete_class API
add Chef::NodeMap#delete_class API

halite needs this public API in order to not be so brittle.

needs tests...

Signed-off-by: Lamont Granquist <0ab8dc438f73addc98d9ad5925ec8f2b97991703@scriptkiddie.org>

gene1wood/chef,Tensibai/chef,Tensibai/chef,nvwls/chef,MsysTechnologiesllc/chef,chef/chef,juliandunn/chef,tomdoherty/chef,tomdoherty/chef,juliandunn/chef,Ppjet6/chef,higanworks/chef,martinisoft/chef,higanworks/chef,Ppjet6/chef,chef/chef,tomdoherty/chef,juliandunn/chef,mwrock/chef,jaymzh/chef,mattray/chef,tomdoherty/chef,MsysTechnologiesllc/chef,higanworks/chef,tomdoherty/chef,jaymzh/chef,Ppjet6/chef,mattray/chef,Ppjet6/chef,nvwls/chef,higanworks/chef,martinisoft/chef,jaymzh/chef,mattray/chef,MsysTechnologiesllc/chef,jaymzh/chef,martinisoft/chef,juliandunn/chef,mwrock/chef,tas50/chef-1,chef/chef,juliandunn/chef,gene1wood/chef,Tensibai/chef,nvwls/chef,tas50/chef-1,gene1wood/chef,nvwls/chef,mwrock/chef,nvwls/chef,mwrock/chef,chef/chef,mattray/chef,tas50/chef-1,higanworks/chef,Tensibai/chef,mattray/chef,gene1wood/chef,MsysTechnologiesllc/chef,Tensibai/chef,martinisoft/chef,tas50/chef-1,Ppjet6/chef,nvwls/chef,martinisoft/chef,Ppjet6/chef