Fix #40, #39: initctl plugin started too early, before /run FS existed

Delay setup of initctl plugin to after the base filesystems are up and
after the bootmisc plugin has run.

This patch factors out the I/O initialization of plugins so it does not
have to run when plugins are loaded.  Instead, plugins can now call this
API to register an I/O callback when they are ready.

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

plugins/initctl.c

@@ -58,6 +58,7 @@ static plugin_t plugin = {
 	.hook[HOOK_BASEFS_UP] = {
 		.cb    = setup
 	},
+	.depends = { "bootmisc", },
 };
 
 static void fifo_open(void)
@@ -183,6 +184,7 @@ static void setup(void *UNUSED(arg))
 	makefifo(FINIT_FIFO, 0600);
 
 	fifo_open();
+	plugin_io_init(&plugin);
 }
 
 PLUGIN_INIT(plugin_init)