title: "pod update" doesn't update to latest version
body: <p>Here is my podfile I use in the project:</p>
  
  <pre><code>source 'https://github.com/CocoaPods/Specs.git'
  platform :ios, '9.0'
  use_frameworks!
  
  pod 'AFNetworking', '~&gt; 2.0'
  pod 'GoogleMaps'
  pod 'MONActivityIndicatorView'
  pod 'NYXImagesKit'
  pod 'MagicalRecord'
  pod 'FBSDKCoreKit'
  pod 'FBSDKShareKit'
  pod 'FBSDKLoginKit'
  pod 'Countly'
  </code></pre>
  
  <p>The problem is that cocoapods 0.39 is updating AFNetworking to version 2.5.4 which is wrong. The latest version is 2.6.3 Also facebook SDK updating to 4.4 (latest is 4.8) etc.</p>
  
  <p>I tried to delete Pods folder and .lock file but doesn't help</p>
  
  <p>Also tried to clean the cocoapods cache but didn't help:</p>
  
  <pre><code>MACMINI:myproject myusername$ pod cache clean --all
  MACMINI:myproject myusername$ pod update
  Update all pods
  Updating local specs repositories
  Analyzing dependencies
  Downloading dependencies
  Installing AFNetworking (2.5.4)
  Installing Bolts (1.2.0)
  Installing Countly (15.06.01)
  Installing FBSDKCoreKit (4.4.0)
  Installing FBSDKLoginKit (4.4.0)
  Installing FBSDKShareKit (4.4.0)
  Installing GoogleMaps (1.10.1)
  Installing MONActivityIndicatorView (0.0.3)
  Installing MagicalRecord (2.3.0)
  Installing NYXImagesKit (2.3)
  Generating Pods project
  Integrating client project
  
  [!] Please close any current Xcode sessions and use `myproject.xcworkspace` for this project from now on.
  Sending stats
  Sending stats
  Pod installation complete! There are 9 dependencies from the Podfile and 10 total pods installed.
  </code></pre>