This patch fixes compilation warning, "conversion from 'time_t' to 'ulong', 
possible loss of data". 
The fix is to typecast time_t to ulong before assigning it to ulong. 
Backported this from 6.0-bugteam tree.


storage/archive/ha_archive.cc:
  type casting time_t to ulong before assigning.
storage/federated/ha_federated.cc:
  type casting time_t to ulong before assigning.
storage/innobase/handler/ha_innodb.cc:
  type casting time_t to ulong before assigning.
storage/myisam/ha_myisam.cc:
  type casting time_t to ulong before assigning.