Fixed spb_pick() to add 0 sized S-Expression even if our position index points to end of the string.
Fixed spb_pick() to add 0 sized S-Expression even if our
position index points to end of the string.

redhatrises/openscap,mpreisler/openscap,jan-cerny/openscap,redhatrises/openscap,OpenSCAP/openscap,redhatrises/openscap,Hexadorsimal/openscap,redhatrises/openscap,mpreisler/openscap,Hexadorsimal/openscap,Hexadorsimal/openscap,Hexadorsimal/openscap,mpreisler/openscap,Hexadorsimal/openscap,Hexadorsimal/openscap,mpreisler/openscap,jan-cerny/openscap,jan-cerny/openscap,redhatrises/openscap,jan-cerny/openscap,redhatrises/openscap,OpenSCAP/openscap,OpenSCAP/openscap,OpenSCAP/openscap,mpreisler/openscap,OpenSCAP/openscap,mpreisler/openscap,jan-cerny/openscap,jan-cerny/openscap,OpenSCAP/openscap