remove swapfiles service

The swapfiles service was basically a copy of the swap service, so this
commit consolidates the functionality into the swap service.

X-Funtoo-Bug-URL: https://bugs.funtoo.org/browse/FL-2523
X-Gentoo-Bug: 568162
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=568162

conf.d/Makefile

@@ -1,7 +1,7 @@
 include ../mk/net.mk
 
 DIR=	${CONFDIR}
-CONF=	bootmisc fsck hostname localmount netmount urandom tmpfiles \
+CONF=	bootmisc fsck hostname localmount netmount swap urandom tmpfiles \
 		${CONF-${OS}}
 
 ifeq (${MKNET},yes)