* lisp/org.el (org-speed-commands-default): Bind "U" and "D" to
`org-metaup' and `org-metadown'.

Org speed keys were not updated to reflect the recent changes to
org-shiftmetaup and org-shiftmetadown.  As a result the default
bindings for speedkeys "U" and "D" were destructive, since they moved
only single lines.  Binding them to org-metaup and org-metadown fixes
the problem.

Thanks to Marco Wahl for reporting the problem:
http://permalink.gmane.org/gmane.emacs.orgmode/87873