using :allocate as allocator on new instances works again

The commit that explicitely disabled it on 1.9+
(02c927c) was very unspecific as to
why it was so. The test passes on 2.0+, so I am reenabling it again.

Closes jimweirich#18

lib/flexmock/partial_mock.rb

@@ -154,7 +154,6 @@ def new_instances(*allocators, &block)
       allocators = [:new] if allocators.empty?
       expectation_recorder = ExpectationRecorder.new
       allocators.each do |allocate_method|
-        check_allocate_method(allocate_method)
         flexmock_define_expectation(location, allocate_method).and_return { |*args|
           create_new_mocked_object(
             allocate_method, args, expectation_recorder, block)
@@ -245,13 +244,6 @@ def flexmock_based_on(*args)
 
     private
 
-    def check_allocate_method(allocate_method)
-      if allocate_method == :allocate && RUBY_VERSION >= "1.9"
-        fail UsageError,
-          "Cannot mock the allocation method using new_instances in Ruby 1.9"
-      end
-    end
-
     # The singleton class of the object.
     def target_singleton_class
       @obj.singleton_class

test/new_instances_test.rb

@@ -117,22 +117,12 @@ def test_does_not_by_default_stub_objects_created_with_allocate
     assert_equal :woof,  m.bark
   end
 
-  if RUBY_VERSION >= "1.9"
-    def test_explicitly_mocking_allocation_in_new_instances_fails_in_ruby_19
-      assert_raise FlexMock::UsageError do
-        flexstub(Dog).new_instances(:allocate) do |obj|
-          obj.should_receive(:bark).and_return(:whimper)
-        end
-      end
-    end
-  else
-    def test_can_explicitly_stub_objects_created_with_allocate
-      flexstub(Dog).new_instances(:allocate) do |obj|
-        obj.should_receive(:bark).and_return(:whimper)
-      end
-      m = Dog.allocate
-      assert_equal :whimper,  m.bark
+  def test_can_explicitly_stub_objects_created_with_allocate
+    flexstub(Dog).new_instances(:allocate) do |obj|
+      obj.should_receive(:bark).and_return(:whimper)
     end
+    m = Dog.allocate
+    assert_equal :whimper,  m.bark
   end
 
   def test_can_stub_objects_created_with_arbitrary_class_methods