Fix a bug where ctx.config['targets'] was looped through again

in connect().  The bug caused vm behavior to happen for a
target if any of the machines in the cluster was a vm.  The code
was also changed to set the key to none only if rsa or dsa keys
were used on a vm.

Fixes: 7113
Signed-off-by: Warren Usui <warren.usui@inktank.com>