tns platform update android fails if no platform is added

[Natalia-Hristova]

Please, provide the details below:

Did you verify this is a real problem by searching the NativeScript Forum and the other open issues in this repo?

Tell us about the problem

When try to update android platform to current official version (4.0.1) comamnd tns platform update android fails:

tns platform update android
The platform android is not added to this project. Please use 'tns platform add <platform>'
# tns platform update

==========

┌──────────────────────────┬─────────────────────────────────────────┐
│ Usage                    │ Synopsis                                │
│ Android latest runtime   │ $ tns platform update android           │
│ Android selected runtime │ $ tns platform update android@<Version> │
│ iOS latest runtime       │ $ tns platform update ios               │
│ iOS selected runtime     │ $ tns platform update ios@<Version>     │
└──────────────────────────┴─────────────────────────────────────────┘

Updates the NativeScript runtime for the specified platform. You must specify the target platform that you want to update.

### Attributes

    * <Platform> is the target mobile platform whose runtime you want to update. You can set the following target platforms.
        * android - Updates the Android runtime.
        * ios - Updates the iOS runtime.
    * <Version> is any available version of the respective platform runtime published in npm. 

Which platform(s) does your issue occur on?

Android

Please provide the following version numbers that your issue occurs with:

• CLI: 4.1.0-2018-05-28-11677

Please tell us how to recreate the issue in as much detail as possible.

1. tns create TestApp
2. tns platform update android

Is there code involved? If so, please share the minimal amount of code needed to recreate the problem.

Consider using the playground to provide the code you have issues with.

[Natalia-Hristova]

Fixed.