When we create a replica file we include in it very security sensitive
information. Then we tell the admin to move it to another machine and
use it.
This info is not cleared from the main server, and it may be forgotten
in a tmp directory on the target server.

Given we need to ask for the Directory Manager password to be able to
install the replica I was thinking it could be a good idea to encrypt
the replica information with the same password and decipher the data
only at installation time, making sure we clean up any temporary file.

This also implicitly proves the Directory Manager password is correct
even before trying to connect to the other server catching an error in
that sense very early on.