Return t if L1, a list specification of a version, is equal to L2.
Note that a version specified by the list (1) is equal to (1 0),
(1 0 0), (1 0 0 0), etc. That is, the trailing zeros are insignificant.
Also, a version given by the list (1) is higher than (1 -1), which in
turn is higher than (1 -2), which is higher than (1 -3).