I don't know if this should be done for 1.4.1 or 1.5.0, but this is primarily to help support
ACCUMULO-404. In a secured installation, there is the assumption that the accumulo user only has rwx access in the /accumulo directory and it's children. Unfortunately, Accumulo only knows how to init with there being no /accumulo directory. While I understand we don't want to worry about clobbering the directory, we should provide a mechanism to init on top of an existing, but empty, /accumulo hdfs directory. This will allow the SA to create an accumulo directory and provide perms appropriately for the accumulo user, rather than having to grant write at the root level and then revoking that permission after initting.