Revision 664943

-- Error recovery code for thrift logfile

Summary:
- perform some basic corruption checks:
   1) Event larger than chunk
   2) Event larger than specified max
   3) Event crossing chunk boundary etc.
- If error encountered, then try to perform some recovery

Reviewed By: Slee

Test Plan: Going to test now...need to check in because of compile issues

Notes:
- These checks take care of the case when there is a dirty read from the filesystem (which
  we have encountered with the netapps). The recovery involves trying to perform the read
  again from ths FS and if that fails skipping the chunk altogether.
  Keep in mind that this might only be useful for idempotent systems (e.g. search redolog).