TEIIDDES-1694: Fix regression in edit server action

* When clicking on a Teiid Server in the ServerView, it should not be
  necessary to display the server selection dialog since the server has
  already been selected using the selection changed listener

* EditServerAction
 * The edit server action should have no knowledge of the default server
   and has no need try and get it itself. In all use-cases it should be
   provided with the server that it is editing.
 * The default constructor is invoked when using the action as a command
   handler. In this case, the server-to-edit is provided by the event's
   data object.
 * Since all use-cases have the server provided, the editDefault flag can
   be removed.

* ModelExplorerResourceNavigator
 * Provide the edit server command with an event containing the server-to-
   be-edited.
Merge pull request #154 from phantomjinx/master

TEIIDDES-1694 fix regression fix