g_nfailedins_ops is never used for anything, remove it for now.
g_nworker_ops isn't used anywhere, discard it.
fix naming for atomic-increment functions, inline them so we're not
paying a function all.
Add some comments to the main routine.
formatting, KNF
Don't reset the counters (and g_running flag) every time we start up
a new set of threads, for the worker phase, we start up to 3 sets of
threads and those values should only set initialized once.

Minor error handling clenaup.
The test if any populate threads failed was wrong, we only complained if
they all failed.  Rework g_threads_quit processing to be the same for the
populate and worker functions,
Don't return from execute_populate or execute_workload without stopping
the threads: returning an error and leaving the threads running is will
core dump when the threads start using a closed WT_CONNECTION structure.
Don't keep running once a worker thread fails, there's no point.
Tighten down the execute_populate() inner loop: don't do any work if
report_interval isn't set, don't do division operations when integer
operations will do.
Don't assume the run-time is a multiple of the report-interval.

Sanity check the run-time value as well as the report-interval.

Now that execute_populate/execute_workload are setting g_running,
Sanity check the run-time and the report-interval before we call the
execute_population function, don't wait until calling execute_workload.
Give each thread its own read/update operations counters so we don't
race on the increments.
Streamline the worker function -- assume we'll succeed and minimize the
work on the way.
Fix wtperf insert_rmw functionality.

There were several bugs before. The idea is to issue a read for each
item prior to doing an insert. It is expected for the read to return
WT_NOTFOUND.
Merge pull request #731 from wiredtiger/wtperf-keith2

Some cleanups for wtperf.