Get date in EnhancedChangesList::recentChangesLine from baseRC

$cachedEntry gets set with baseRC, so baseRC timestamp is the
same as $cachedEntry timestamp.

Doing things this way makes it more feasible to split out some
of the change formatting code.

Change-Id: I1cae6174c827802d525bb95ed152c64008ce7360
Create cachedEntry after processing change block

Change-Id: I8b6b85104f15eb8325abace9b0a0653e16d748b9
Merge changes I8b6b8510,I1cae6174

* changes:
  Create cachedEntry after processing change block
  Get date in EnhancedChangesList::recentChangesLine from baseRC