Fix regression introduced in version 0.86.
The regression was a
side-effect of funtionality added to keep the pipe open to the
command executed by p4jrep. The regression caused the journal
position to be erroneously updated when the forked process
exited with a non-zero exit code. This could result in journal
entries missed when restarting replication following a failure
of the command executed by p4jrep.
Credit (and my thanks) goes to Brian Moyers for finding and
diagnosing the regression, and coding and testing the fix.