Fix comment typos in test 517

83: Wed, 31 Dec 2008 23:59:60 GMT => 1230768000

</stdout>

# This test case previously testes an overflow case ("2094 Nov 6 =>

# This test case previously tested an overflow case ("2094 Nov 6 =>

# 2147483647") for 32bit time_t, but since some systems have 64bit time_t and

# handles this (returning 3939840000), and some 64bit-time_t systems don't

# handle this and returns -1 for this, it turned very tricky to write a fine

# handle this and return -1 for this, it turned very tricky to write a fine

# test case and thus it is now removed until we have a way to write test cases

# for this kind of things.