Fix standard logger format.
Fix standard logger format.

jlfaber/grape,fangzhu19880123/grape,ruby-grape/grape,peterwillcn/grape,shunyam/grape,thogg4/grape,gencer/grape,dblock/grape,dslh/grape,namusyaka/grape,intridea/grape,niedhui/grape,rnubel/grape,reynardmh/grape,klaustopher/grape