nailgun script fails when angular2 CLI is installed

[kgignatyev-inspur]

Angular CLI makes 'ng' command available and it causes nailgun script to fail
https://cli.angular.io/

Simplest fix is to disable check for ng existence:

check whether we have an ng command

#do not check as it collides with ng from angular
#function ng_exists {
#type -P $ng_cmd > /dev/null 2>&1
#}
ng_exists=false;