Replication Manager installer does not warn when installing in an existing directory or when the target directory does not exist

[CR #532570] The Replication Manager 15.2 installation program does not display a warning when installing in an existing directory. However, the installation program displays a warning if an earlier version of Replication Manager is installed in the installation directory. Also, the installation program does not display a confirmation message to create a new directory if the target installation directory does not exist.