Stop over-managing user SSH keyfiles

* modules/user/manifests/virtual/localuser.pp: This reverts part of
0d82c62 which was providing a temporary transition correcting
permissions and ownership as well as removing the results of a
previous failed implementation of keyfile management. Unfortunately
that also caused nodepool images to no longer set up accounts
correctly, but reverting the transitional bits fixes that issue.

Change-Id: Ic3e7f0a3b82bbc8a23707b88f9fe381e9d70e356