app: logs: Re-work the log file setup
app: logs: Re-work the log file setup

Simplify the logic somewhat by only opening the files in append
mode, this will create the files if they don't exist.

When starting up, check that we can access the log directory, if we
can't, exit().

Signed-off-by: Andrew Clayton <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@opentechlabs.co.uk>

ac000/fcgi_app_core,ac000/fcgi_app_core