Fixed error where a statement was closed twice. JM-896

git-svn-id: http://svn.igniterealtime.org/svn/repos/wildfire/trunk@6099 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/wildfire/roster/RosterItemProvider.java

@@ -320,6 +320,7 @@ public class RosterItemProvider {
                 rs.close();
                 // Close the prepared statement
                 pstmt.close();
+                pstmt = null;
             }
         }
         catch (SQLException e) {