A local variable is not set before use in Game._log_algebraic_notation_pawn_move() method.

[RogerMarsh]

Spotted while seeing what Cython made of the game module.

[RogerMarsh]

The unittest added to document the problem did not fail.

The code which would fail seems unreachable in practice at runtime. The GameTextPGN class spots the moves, 'e7xf8=Q' for example, correctly via a different method.