cpp/Sequence: fix memory leak in exception catch
cpp/Sequence: fix memory leak in exception catch

catch-block used to call luaL_error, which resulted in
leaking of exception object (luaL_error does not call
destructors while unwinding stack).

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