Remove unused sanitiser test

The sanitiser got removed at some point, but the tests remained.

test/unit/sanitiser/_private.js

@@ -1,53 +0,0 @@
-var sanitize = require('../../../sanitiser/_private');
-
-module.exports.tests = {};
-
-module.exports.tests.sanitize_private = function(test, common) {
-  var invalid_values = [null, -1, 123, NaN, 'abc'];
-  invalid_values.forEach(function(privateValue) {
-    test('invalid private param ' + privateValue, function(t) {
-      var req = {query: { private: privateValue }};
-      sanitize(req);
-      t.equal(req.clean.private, false, 'default private set (to false)');
-      t.end();
-    });
-  });
-
-  var valid_values = ['true', true, 1, '1', 'yes', 'y'];
-  valid_values.forEach(function(privateValue) {
-    test('valid private param ' + privateValue, function(t) {
-      var req = {query: { private: privateValue }};
-      sanitize(req);
-      t.equal(req.clean.private, true, 'private set to true');
-      t.end();
-    });
-  });
-
-  var valid_false_values = ['false', false, 0, '0', 'no', 'n'];
-  valid_false_values.forEach(function(privateValue) {
-    test('test setting false explicitly ' + privateValue, function(t) {
-      var req = {query: { private: privateValue }};
-      sanitize(req);
-      t.equal(req.clean.private, false, 'private set to false');
-      t.end();
-    });
-  });
-
-  test('test default behavior', function(t) {
-    var req = {query: {}};
-    sanitize(req);
-    t.equal(req.clean.private, true, 'private set to true');
-    t.end();
-  });
-};
-
-module.exports.all = function (tape, common) {
-
-  function test(name, testFunction) {
-    return tape('SANTIZE _private ' + name, testFunction);
-  }
-
-  for( var testCase in module.exports.tests ){
-    module.exports.tests[testCase](test, common);
-  }
-};