Clean up the svn-alist widget type, as hinted in r16610.
Clean up the svn-alist widget type, as hinted in r16610.

* contrib/client-side/psvn/psvn.el
  (svn-alist): Made the check for the `alist' widget type more robust against
    autoloading, at the cost of loading wid-edit earlier than necessary.
  (svn-alist-convert-widget): Don't coerce the :key-type and :value-type
    properties to lists.  That was needed only for the svn-alist-match
    function, which never made it to the trunk.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion