[PATCH] Clean up overflow stats message

[Maynard J. <may...@us...>]

More than one user has reported confusion concerning the warning message "Overflow stats not available" that can occur if you use opreport before the stats files are copied to <session-dir>/samples/current.  Currently, the stats files are not copied over until 'opcontrol --shutdown (or --deinit)'.  Thus, if a user does 'opcontrol --dump' and then 'opreport', the stats files will not have been copied yet, so they'll get the pointless message.  What's worse is that if there actually *were* overflows that occurred, they won't get the warning about that, which is what we really want.

The attached patch moves the copying of the stats files do opcontrol's do_dump_data routine.  This routine gets called anytime the user does --dump, --stop, --shutdown, or --deinit.  The multiple times the files are copied is actually a good thing, since at each of these stages, new samples may have been collected, so we should have updated stats that correspond with the new samples.

Review comments are welcome.

Thanks.
-Maynard

Signed-off-by:  Maynard Johnson <may...@us...>