services: Add missing returns

service/clipboard.lua

@@ -15,3 +15,4 @@ function start()
    end
  end)
 end
+return {start=start}

service/screenblank.lua

@@ -23,3 +23,4 @@ function start()
   end
  end, "screenblank")
 end
+return {start=start}

service/tape-devfs.lua

@@ -16,6 +16,9 @@ end
 for addr in component.list("tape_drive") do
  addNode(addr)
 end
+
+function start()
+ return os.spawn(function()
   while true do
    local tE = {coroutine.yield()}
    if tE[1] == "component_added" and tE[3] == "tape_drive" then
@@ -26,3 +29,6 @@ while true do
     end
    end
   end
+ end, "tape-devfs")
+end
+return {start=start}

service/termsrv.lua

@@ -61,3 +61,4 @@ function start()
  end
  end,"termsrv")
 end
+return {start=start}

service/wolbeacon.lua

@@ -6,6 +6,8 @@ for modem in component.list("modem") do
  component.invoke(modem,"setWakeMessage",message)
 end
 
+function start()
+ return os.spawn(function()
   local ltime = computer.uptime()
   while true do
    if computer.uptime() > ltime+delay then
@@ -16,3 +18,6 @@ while true do
    end
    coroutine.yield()
   end
+ end, "WoLBeacon")
+end
+return {start=start}