Allow creating private keys and directory with g+rX about uacme

[ndilieto]

uacme sets permissions on keys and directories only when it creates them. It never touches permissions of an existing file or directory. You are therefore free to change permissions as you like. Note there is also an option (-n) that prevents uacme from creating any file or directory. This is useful if you'd like to provide your own keys, which you can generate with openssl or gnutls.