[Podspec] Remove AnimationExperimental subspec and fix Image subspec

Summary:
AnimationExperimental is gone; remove it. The Image subspec now depends on the networking code, so we have to pull in those files. These changes were necessary to publish 0.10.0-rc to CocoaPods, so would be convenient to get them into master for 0.11.

Fixes #2354
Closes https://github.com/facebook/react-native/pull/2341
Github Author: James Ide <ide@jameside.com>

React.podspec

@@ -58,7 +58,8 @@ Pod::Spec.new do |s|
 
   s.subspec 'RCTImage' do |ss|
     ss.dependency         'React/Core'
-    ss.source_files     = ["Libraries/Image/*.{h,m}", "Libraries/Network/*.{h,m}"]
+    ss.dependency         'React/RCTNetwork'
+    ss.source_files     = "Libraries/Image/*.{h,m}"
     ss.preserve_paths   = "Libraries/Image/*.js"
   end