Fix test failures resulting from trying to query DB in tools that don't use a

specific collection (dump/restore).

tools/tool.cpp

@@ -383,7 +383,10 @@ namespace mongo {
         if ( ! ( _username.size() || _password.size() ) ) {
             // Make sure that we don't need authentication to connect to this db
             // findOne throws an AssertionException if it's not authenticated.
-            conn().findOne(getNS(), Query("{}"));
+            if (_coll.size() > 0) {
+                // BSONTools don't have a collection
+                conn().findOne(getNS(), Query("{}"));
+            }
             return;
         }