r22914: - Fixes bug 4599. A missing <code>if</code> statement forced subseqeuent

r22914: - Fixes bug 4599.  A missing <code>if</code> statement forced subseqeuent
  attempts to set attributes to fail.

- I also noticed that missing attributes were setting an invalid return string
  by getxattr(), e.g. if there was not group, the return string had "GROUP:;"
  instead of excluding the GROUP attribute entirely as it should.  The big
  problem with the way it was, is that the string could not then be passed to
  setxattr() and parsed.
(This used to be commit 7213b5ebec8cd7f1955f5aa8ee4050c39cd11ed1)