Issue 164: syslog plugin needs to be loaded as first plugin

[txaj]

If the syslog plugin is not initialized as first plugin, other plugins
won't be able to log their startup/fail output at load time.

reported by bzed

[blkperl]

Is there some way to get tests for this? A comment would be nice to explain why it is first.

[bzed]

why: man 5 collectd.conf:

The configuration is read and processed in order, i.e. from top to bottom. So the plugins are loaded in the order listed in this config file. It is a good idea to load any logging plugins first in order to catch messages from plugins during configuration. Also, the LoadPlugin option must occur before the appropriate  block.

actually it might make sense to load the logfile plugin at order 00, too.

[txaj]

well catched bzed.
Also after giving it a thought, it'd be nice to still let the user still to load something before those plugins if he wants to. Since the default order is 10, I suggest we put a default of 05 for both syslog and logfile