Migrate testserv plugin to a couple of lines of ASCII .conf files

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

system/.gitignore

@@ -0,0 +1,2 @@
+Makefile
+Makefile.in

system/Makefile.am

@@ -0,0 +1,6 @@
+systemdir         = $(system_path)
+dist_system_DATA  =
+
+if BUILD_TESTSERV_PLUGIN
+dist_system_DATA += testserv.conf
+endif

system/testserv.conf

@@ -0,0 +1,4 @@
+# Test service, only used for `make check`, not for public use
+service [S123456789] name:testserv pid:!/run/testserv.pid \
+	<boot/testserv> cgroup.system \
+	/sbin/serv -n -p -i testserv -- Test serv daemon