commands: container-hosts must be normalized in add cluster

when running rocks add cluster the list of containers must be
normalized so that it uses only internal DB hostname
commands: airboss logger must be closed after fork

half a day of debugging... to discover that after you fork
you need to close the logger if not in a random way it will
write to it's old fileno which after the fork is probably
something else.

This was closing the waiting server socket in a random way.
commands: airboss close syslog connection before forking

syslog keeps an active connection to the logger but after the fork
all connection are closed so when it tries to write again it was
sending data to an invalid connection (terminating the database!!)
commands: airboss close all DB connection before forking

The database connection must be close before we fork or when it
will be used again it will fail since the connection was closed
after the fork
commands: airboss catch exception set cdrom

properly handle error in set cdrom