Clean up the printerr() logging function.

Clean up the printerr() logging function.

Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Update the printerr() function to:

1) Determine whether we'll print the message before going to all the
   work of formatting it.
2) Don't just toss away messages that are too long for the buffer.
   Print what we can and give an indication of the truncation with
   "..." at the end.
3) Use a single buffer rather than two.
4) Messages either go to syslog (with level ERR) or stderr.  Don't
   send some messages to syslog level DEBUG.