Fix Dataset#empty? for ordered Datasets on Oracle
Fix Dataset#empty? for ordered Datasets on Oracle

mpalmer/sequel,freshpay/sequel,freshpay/sequel,seeARMS/sequel,yazshel/sequel,uhoh-itsmaciek/sequel,knut2/sequel,offshore-safety/sequel,beni55/sequel,nicohvi/sequel,davidbegin/sequel,knut2/sequel,dennis-d/custom_sequel,yazshel/sequel,nicohvi/sequel,dennis-d/custom_sequel,seeARMS/sequel,gferguson-gd/sequel,reubano/sequel,reubano/sequel,pfarrell/sequel,bigfix/sequel,beni55/sequel,mpalmer/sequel,uhoh-itsmaciek/sequel,Marketcircle/sequel,chef/sequel,offshore-safety/sequel,gferguson-gd/sequel,t-morgan/sequel,t-morgan/sequel,davidbegin/sequel,pfarrell/sequel,nju520/sequel,offshore-safety/sequel,nju520/sequel