throw TLogUnexcpectedEndOfFile when reaching the end of the tlog unexpectedly, and treat as a TLogCheckSumError in most places
This fixes a bug in truncating introduced in 2f2371e305f677a17c4c19e32b82f38fdc5b9369
Merge remote-tracking branch 'refs/remotes/origin/ARAKOON-413' into 1.6