[j-nsp] understand "request system software rollback" in Junos

[Markus]

Am 01.10.2015 um 18:25 schrieb Martin T:
> When can one use "request system software rollback"?

http://www.juniper.net/documentation/en_US/junos13.3/topics/reference/command-summary/request-system-software-rollback.html

"A software rollback fails if any required package (or a jbundle package 
containing the required package) cannot be found in /var/sw/pkg."