Remove deprecated TYPE in rest_client

This commit removes the deprecated TYPE variable in rest_client. We
already deprecated this last year[1]. So I think we can remove this.

[1] I8a2e21d6c87a58b0335dbc66bb5a242953dfbd14

Change-Id: Ieb713513dd0e01e7a634ead890a50cc0c72b5dea
diff --git a/tempest/lib/common/rest_client.py b/tempest/lib/common/rest_client.py
index 99ba6ab..d72b4dd 100644
--- a/tempest/lib/common/rest_client.py
+++ b/tempest/lib/common/rest_client.py
@@ -70,7 +70,6 @@
     :param str http_timeout: Timeout in seconds to wait for the http request to
                              return
     """
-    TYPE = "json"
 
     # The version of the API this client implements
     api_version = None
@@ -105,12 +104,6 @@
             disable_ssl_certificate_validation=dscv, ca_certs=ca_certs,
             timeout=http_timeout)
 
-    def _get_type(self):
-        if self.TYPE != "json":
-            self.LOG.warning("Tempest has dropped XML support and the TYPE "
-                             "became meaningless")
-        return self.TYPE
-
     def get_headers(self, accept_type=None, send_type=None):
         """Return the default headers which will be used with outgoing requests
 
@@ -125,9 +118,9 @@
                  dict for outgoing request
         """
         if accept_type is None:
-            accept_type = self._get_type()
+            accept_type = 'json'
         if send_type is None:
-            send_type = self._get_type()
+            send_type = 'json'
         return {'Content-Type': 'application/%s' % send_type,
                 'Accept': 'application/%s' % accept_type}
 
diff --git a/tempest/tests/lib/test_rest_client.py b/tempest/tests/lib/test_rest_client.py
index 4a83631..43bb6d0 100644
--- a/tempest/tests/lib/test_rest_client.py
+++ b/tempest/tests/lib/test_rest_client.py
@@ -91,18 +91,15 @@
 
 
 class TestRestClientHeadersJSON(TestRestClientHTTPMethods):
-    TYPE = "json"
 
     def _verify_headers(self, resp):
-        self.assertEqual(self.rest_client._get_type(), self.TYPE)
         resp = dict((k.lower(), v) for k, v in six.iteritems(resp))
         self.assertEqual(self.header_value, resp['accept'])
         self.assertEqual(self.header_value, resp['content-type'])
 
     def setUp(self):
         super(TestRestClientHeadersJSON, self).setUp()
-        self.rest_client.TYPE = self.TYPE
-        self.header_value = 'application/%s' % self.rest_client._get_type()
+        self.header_value = 'application/json'
 
     def test_post(self):
         resp, __ = self.rest_client.post(self.url, {})