Steps to reproduce:

1. Create a host with at least one tag.
2. Make API request to host.get and specify selectTags query option to retrieve a tag only: selectTags = ['tag'].

Result:

1. PHP Notice: Undefined index: value in C:\WebDev\Sites\n3022\ui\include\classes\api\services\CHostGeneral.php on line 858
2. value = NULL returned by API.

Expected:

1. No PHP errors reported.
2. Only a tag property returned by API.