Change random passwords behaviour
Improved options checking so that host-mod operation is not changing
password for enrolled host when '--random' option is used.
Unit tests added.
https://fedorahosted.org/freeipa/ticket/2799
Updated set of characters that is used for generating random passwords
for ipa hosts. All characters that might need escaping were removed.
https://fedorahosted.org/freeipa/ticket/2800