Clear message when a recovery target is missed

[dwsteele]

When doing time-based recovery and the time is not found before the end of WAL postgres does not note that the recovery point was missed:

LOG:  starting point-in-time recovery to 2016-06-11 15:37:23.640446+00
LOG:  restored log file "00000002.history" from archive
LOG:  restored log file "000000020000000000000006" from archive
LOG:  redo starts at 0/6000028
LOG:  consistent recovery state reached at 0/60000F0
LOG:  incomplete startup packet
LOG:  redo done at 0/60000F0

It would be nice to get a warning in the log that the PITR was not successful, even though recovery was.