Fix ktime test on 64-bit systems

Fix ktime test on 64-bit systems

0xffffffff is a bad representation for -1 when the size of the data
type may vary.  Rather than forcing everything to 32 bits and losing
later on platforms with 64-bit time_t, change the table to use time_t
and try to add a cast that will do the right thing.

Change-Id: Id532c9b7a1fc215dc9fd532592fecb2ea45597a0
Reviewed-on: http://gerrit.openafs.org/2420
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>