don't pass web3 object to whisper module since it uses its own

lib/core/engine.js

@@ -262,11 +262,7 @@ class Engine {
       web3: options.web3
     });
 
-    this.registerModule('whisper', {
-      // TODO: this should not be needed and should be deducted from the config instead
-      // the eth provider is not necessary the same as the whisper one
-      web3: this.blockchain.web3
-    });
+    this.registerModule('whisper');
   }
 
   libraryManagerService(_options) {