Fix a bug when setting GRPCCall.state = GRXWriterStateFinished

src/objective-c/GRPCClient/GRPCCall.m

@@ -185,9 +185,6 @@ static NSString * const kBearerPrefix = @"Bearer ";
 
 - (void)finishWithError:(NSError *)errorOrNil {
   @synchronized(self) {
-    if (_state == GRXWriterStateFinished) {
-      return;
-    }
     _state = GRXWriterStateFinished;
   }