Fix bug 1383405 and bug 1383597

Bug 1383405: trafodion_mods now checks to see if on a single node
cluster before creating log directories.

Bug 1383597: traf_hortonworks_uninstaller now looks to make sure
there is something to delete before deleting the file.

Change-Id: Ic8a1761d50dbf34aad0d042a09bdd5a11a74d387