Fix crash with iterator
Fix crash with iterator

When passing a nil parameter to move_to, the application was aborting.
The parameter need to be checked in the Lua wrapper.

lcheylus/haka,Wingless-Archangel/haka,nabilbendafi/haka,LubyRuffy/haka,haka-security/haka,Wingless-Archangel/haka,nabilbendafi/haka,lcheylus/haka,lcheylus/haka,nabilbendafi/haka,haka-security/haka,LubyRuffy/haka,haka-security/haka