If the file isn't closed such as when logging to stdout or stderr the file must be flushed for it to get out of the IO buffers right away.

Signed-off-by: Florian Forster <octo@collectd.org>
logfile plugin: Make "do_close" a boolean.
cpu plugin: Remove broken debug message.

The message was uninformative and did cast a pointer to an int,
resulting in a compile error.
curl's numeric options are always at minimum long, never int

This can affect portability to some architectures.

Signed-off-by: Florian Forster <octo@collectd.org>
Merge branch 'collectd-4.10' into collectd-5.1

Conflicts:
	src/curl_json.c
src/plugin.c: Initialize "next_read" field of read callbacks.

Fixes Github issue #230.