newsyslog.conf: Restrict included files in default config to [!.]*.conf

The new default config will only include files from the following
directories which end with '.conf' and do not beginning with a '.'
character:
- /etc/newsyslog.conf.d/
- /usr/local/etc/newsyslog.conf.d/

This matches the syslog.conf(5) functionality, and also prevents '.sample' or
'.pkgnew' files being included. This is important for ports which install files
in /usr/local/etc/newsyslog.conf.d/ and also for pkgbase.

Approved by:	eadler
Approved by:	bapt
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D17086

usr.sbin/newsyslog/newsyslog.8

@@ -17,7 +17,7 @@
 .\" the suitability of this software for any purpose.  It is
 .\" provided "as is" without express or implied warranty.
 .\"
-.Dd July 19, 2018
+.Dd November 10, 2018
 .Dt NEWSYSLOG 8
 .Os
 .Sh NAME
@@ -268,10 +268,12 @@ will examine all files listed in the configuration file.
 .Nm
 configuration file
 .It Pa /etc/newsyslog.conf.d
-Each file in this directory will be included by the default
+By default each file in this directory ending in '.conf' and not beginning with
+a '.' will be included by the default
 .Pa newsyslog.conf .
 .It Pa /usr/local/etc/newsyslog.conf.d
-Each file in this directory will be included by the default
+By default each file in this directory ending in '.conf' and not beginning with
+a '.' will be included by the default
 .Pa newsyslog.conf .
 .El
 .Sh COMPATIBILITY

usr.sbin/newsyslog/newsyslog.conf

@@ -31,5 +31,5 @@
 /var/log/utx.log			644  3	   *	@01T05 B
 /var/log/weekly.log			640  5	   *	$W6D0 JN
 
-<include> /etc/newsyslog.conf.d/*
-<include> /usr/local/etc/newsyslog.conf.d/*
+<include> /etc/newsyslog.conf.d/[!.]*.conf
+<include> /usr/local/etc/newsyslog.conf.d/[!.]*.conf