Support :librarian option in `solo bootstrap`
Support :librarian option in `solo bootstrap`

PR #180 added `--no-librarian` option to the cook command. If the
bootstrap command does not know about the key, the value will be set to nil
thus disabling `librarian-chef install`. This fixes it (and integration
tests.)

analog-analytics/knife-solo,leonid-shevtsov/knife-solo,leonid-shevtsov/knife-solo,chadzilla2080/knife-solo,analog-analytics/knife-solo,coletivoEITA/knife-solo,analog-analytics/knife-solo,chadzilla2080/knife-solo,a2ikm/knife-solo,a2ikm/knife-solo,a2ikm/knife-solo,matschaffer/knife-solo,leonid-shevtsov/knife-solo,matschaffer/knife-solo,coletivoEITA/knife-solo,coletivoEITA/knife-solo,chadzilla2080/knife-solo,matschaffer/knife-solo