Custom spam tag subject munging in spamassasin plugin

[Jonathan Martens]

Hi all!

I have written a patch to allow the spamassasin plugin to have a custom 
spam tag read in from a configuration file as opposed to the default *** 
SPAM *** that is hard coded.

When the configuration file (spamsubjectprefix) is not defined or empty 
the default value still applies, if it is provided the value from the 
configuration file is used.

Any change this can be considered for implementation as we would really 
like to have it for SME Server.

Kind regards,

Jonathan