Fix luacheck warning.
Fix luacheck warning.

cmusatyalab/openface,cmusatyalab/openface,nhzandi/openface,xinfang/face-recognize,Alexx-G/openface,nhzandi/openface,Alexx-G/openface,cmusatyalab/openface,Alexx-G/openface,nmabhi/Webface,francisleunggie/openface,nmabhi/Webface,nmabhi/Webface,francisleunggie/openface,nmabhi/Webface,nhzandi/openface,Alexx-G/openface,francisleunggie/openface,xinfang/face-recognize,xinfang/face-recognize