sa-learn: Add documentation

Add POD documentation and tidy up

plugins/other/sa-learn

@@ -1,6 +1,41 @@
 #!/bin/bash
+
+: <<=cut
+=head1 NAME
+
+sa-learn - Munin plugin to monitor spamassasin bayes database size
+
+=head1 APPLICABLE SYSTEMS
+
+Any server running spamassassin
+
+=head1 CONFIGURATION
+
+This plugin assumes your Spamassassin database is in /var/lib/MailScanner.
+If it's elsewhere (or you want to use a different database) you will need
+a configuration such as:
+
+   [sa-learn]
+      env.BayesDir /path/to/bayes/directory/
+      user mail
+
+(where 'user mail' refers to a user that can read the database).
+
+=head1 MAGIC MARKERS
+
 #%# family=contrib
 
+=head1 VERSION
+
+2
+
+=head1 AUTHOR
+
+Paul Saunders L<darac+munin@darac.org.uk>
+
+=cut
+#'
+
 case $1 in
 	config)
 		cat <<'EOM'
@@ -21,7 +56,7 @@ esac
 ## Print values
 BayesDir=${BayesDir:-/var/lib/MailScanner}
 
-sa-learn --dbpath $BayesDir --dump magic 2>/dev/null | while read line
+sa-learn --dbpath $BayesDir/ --dump magic 2>/dev/null | while read line
 do
 	case "$line" in
 		*nspam*)