Changes implementation of two overloads of `Disposables.create()` to avoid deprecation warnings.

RxSwift/Disposables/AnonymousDisposable.swift

@@ -36,7 +36,13 @@ public final class AnonymousDisposable : DisposeBase, Cancelable {
         _disposeAction = disposeAction
         super.init()
     }
-
+    
+    // Non-deprecated version of the constructor, used by `Disposables.create(with:)`
+    private init(disposeAction: DisposeAction) {
+        _disposeAction = disposeAction
+        super.init()
+    }
+    
     /**
     Calls the disposal action if and only if the current instance hasn't been disposed yet.
 
@@ -53,3 +59,11 @@ public final class AnonymousDisposable : DisposeBase, Cancelable {
         }
     }
 }
+
+public extension Disposables {
+    
+    static func create(with action: () -> ()) -> Disposable {
+        return AnonymousDisposable(disposeAction: action)
+    }
+    
+}

RxSwift/Disposables/Disposables.swift

@@ -14,12 +14,10 @@ public struct Disposables {
 
 public extension Disposables {
     
-    static func create() -> Disposable {
-        return NopDisposable.instance
-    }
+    private static let noOp: Disposable = NopDisposable()
     
-    static func create(with action: () -> ()) -> Disposable {
-        return AnonymousDisposable(action)
+    static func create() -> Disposable {
+        return noOp
     }
     
     static func create(_ disposable1: Disposable, _ disposable2: Disposable, _ disposable3: Disposable) -> Disposable {