Remove unused variable in static constructors
diff --git a/src/AddressBook/AddressBookProtos.cs b/src/AddressBook/AddressBookProtos.cs
index 5c69ace..468f5a5 100644
--- a/src/AddressBook/AddressBookProtos.cs
+++ b/src/AddressBook/AddressBookProtos.cs
@@ -357,7 +357,7 @@
           }
         }
         static PhoneNumber() {
-          pbd::FileDescriptor descriptor = global::Google.ProtocolBuffers.Examples.AddressBook.AddressBookProtos.Descriptor;
+          object.ReferenceEquals(global::Google.ProtocolBuffers.Examples.AddressBook.AddressBookProtos.Descriptor, null);
         }
       }
       
@@ -707,7 +707,7 @@
       }
     }
     static Person() {
-      pbd::FileDescriptor descriptor = global::Google.ProtocolBuffers.Examples.AddressBook.AddressBookProtos.Descriptor;
+      object.ReferenceEquals(global::Google.ProtocolBuffers.Examples.AddressBook.AddressBookProtos.Descriptor, null);
     }
   }
   
@@ -949,7 +949,7 @@
       }
     }
     static AddressBook() {
-      pbd::FileDescriptor descriptor = global::Google.ProtocolBuffers.Examples.AddressBook.AddressBookProtos.Descriptor;
+      object.ReferenceEquals(global::Google.ProtocolBuffers.Examples.AddressBook.AddressBookProtos.Descriptor, null);
     }
   }