Fix failing prepend test

The prepend test is failing when jenkins runs kithchen but is passing in
my test environment. Make sure each test starts without the 'etc' path
existing.

tests/unit/states/test_file.py

@@ -61,6 +61,15 @@ class TestFileState(TestCase, LoaderModuleMockMixin):
             }
         }
 
+    def tearDown(self):
+        remove_dir = '/etc'
+        if salt.utils.is_windows():
+            remove_dir = 'c:\\etc'
+        try:
+            os.remove(remove_dir)
+        except OSError:
+            pass
+
     def test_serialize(self):
         def returner(contents, *args, **kwargs):
             returner.returned = contents
@@ -1174,6 +1183,7 @@ class TestFileState(TestCase, LoaderModuleMockMixin):
         '''
         Test to ensure that some text appears at the beginning of a file.
         '''
+        assert not os.path.exists('c:\\etc')
         name = '/etc/motd'
         if salt.utils.is_windows():
             name = 'c:\\etc\\motd'