monitor: Use 'device' in eject

Monitor's eject command uses 'filename' for the device name
argument, but 'device' is a better name.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/qemu-monitor.hx b/qemu-monitor.hx
index c788c73..338e30e 100644
--- a/qemu-monitor.hx
+++ b/qemu-monitor.hx
@@ -130,7 +130,7 @@
 
     {
         .name       = "eject",
-        .args_type  = "force:-f,filename:B",
+        .args_type  = "force:-f,device:B",
         .params     = "[-f] device",
         .help       = "eject a removable medium (use -f to force it)",
         .user_print = monitor_user_noop,