[collectd] collection4 nitpicking

[Trent W. Buck]

I've just replaced collection 3 with collection 4.0.0+34, and on the
whole I am impressed.

I notice that /etc/collection.conf starts with CacheFile
"/tmp/collection4.json", which immediately sets off my spidey security
senses[0].  Would it be better to a different default, such as
/var/cache/collection/collection.json?

[0] http://www.dwheeler.com/secure-programs/Secure-Programs-HOWTO/avoid-race.html

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Secondly, why is FastCGI being used?  My life would be easier if
collection4 was an "app server", i.e. it was a permanently-running
daemon that spoke HTTP to the "real" web server, being a reverse proxy
like varnish, nginx or apache mod_proxy.

I ended up putting apache on the collection server simply to translate
FastCGI calls into HTTP requests.  I realize that FastCGI is
theoretically networkable, but IIRC setting it up is a PITA and allows
anyone on the local network to execute arbitrary programs on the
server -- though maybe that's just php5-cgi...