Always source rc.subr to be able to use the rc.conf parsing routine

to get the network related vars from rc.conf. This is even necessary
if netstart is run from within /etc/rc. Remove test of $INRC which
unintentionally evaluated always to true.
problem with previous change found by nigel@
OK sthen@ aja@ halex@

src/etc/netstart

@@ -1,6 +1,6 @@
 #!/bin/sh -
 #
-#	$OpenBSD: netstart,v 1.150 2015/07/19 14:17:21 ajacoutot Exp $
+#	$OpenBSD: netstart,v 1.151 2015/07/19 19:52:36 rpe Exp $
 
 # Strip comments (and leading/trailing whitespace if IFS is set) from a file
 # and spew to stdout.
@@ -148,8 +148,8 @@ ifmstart() {
 	done
 }
 
-# Re-read rc.subr if we are not inside /etc/rc.
-[ -n ${INRC} ] && FUNCS_ONLY=1 . /etc/rc.d/rc.subr
+# Get network related vars from rc.conf using the parsing routine from rc.subr.
+FUNCS_ONLY=1 . /etc/rc.d/rc.subr
 _rc_parse_conf
 
 # If we were invoked with a list of interface names, just reconfigure these