Make the credential storage change action public.

Bug: 6009802

When the credential storage changes, (adding/removing certs,
resetting the storage, enabling/disabling trusted CAs, etc), the
applications that use the storage has to be made aware of the
fact that the storage changed, so they can clear any cached state,
close connections or take any other actions. Internally, this
applies to webview. However, applications, potentially including
3rd party browsers, also need this information.

Change-Id: I765b97a3f38f45247ee3f6e127b490388d373847

keystore/java/android/security/KeyChain.java

@@ -169,7 +169,6 @@ public final class KeyChain {
 
 
     /**
-     * @hide TODO This is temporary and will be removed
      * Broadcast Action: Indicates the trusted storage has changed. Sent when
      * one of this happens:
      *