change code for luacov
change code for luacov

luacov thinks that the following lines
of code are not covered:

*   return a
        :foo()

    local f = function()
*       return 1
    end

starius/lua-npge,npge/lua-npge,npge/lua-npge,npge/lua-npge,starius/lua-npge,starius/lua-npge