complete deprecation of CRLExtensionOID in favor of CRLEntryExtensionOID

Deprecated in 1.2, removed in 1.4 per policy.
diff --git a/src/cryptography/utils.py b/src/cryptography/utils.py
index 5379573..3407bfe 100644
--- a/src/cryptography/utils.py
+++ b/src/cryptography/utils.py
@@ -15,7 +15,6 @@
 # the functions deprecated in 1.0 are on an arbitrarily extended deprecation
 # cycle and should not be removed until we agree on when that cycle ends.
 DeprecatedIn10 = DeprecationWarning
-DeprecatedIn12 = DeprecationWarning
 
 
 def read_only_property(name):
diff --git a/src/cryptography/x509/__init__.py b/src/cryptography/x509/__init__.py
index 8d7bad2..968d29d 100644
--- a/src/cryptography/x509/__init__.py
+++ b/src/cryptography/x509/__init__.py
@@ -4,7 +4,6 @@
 
 from __future__ import absolute_import, division, print_function
 
-from cryptography import utils
 from cryptography.x509.base import (
     Certificate, CertificateBuilder, CertificateRevocationList,
     CertificateRevocationListBuilder,
@@ -38,13 +37,6 @@
 )
 
 
-CRLExtensionOID = utils.deprecated(
-    CRLEntryExtensionOID,
-    __name__,
-    "CRLExtensionOID has been renamed to CRLEntryExtensionOID",
-    utils.DeprecatedIn12
-)
-
 OID_AUTHORITY_INFORMATION_ACCESS = ExtensionOID.AUTHORITY_INFORMATION_ACCESS
 OID_AUTHORITY_KEY_IDENTIFIER = ExtensionOID.AUTHORITY_KEY_IDENTIFIER
 OID_BASIC_CONSTRAINTS = ExtensionOID.BASIC_CONSTRAINTS
@@ -174,7 +166,6 @@
     "OID_CA_ISSUERS",
     "OID_OCSP",
     "_GENERAL_NAMES",
-    "CRLExtensionOID",
     "CertificateIssuer",
     "CRLReason",
     "InvalidityDate",
diff --git a/src/cryptography/x509/oid.py b/src/cryptography/x509/oid.py
index ced1510..48e9d69 100644
--- a/src/cryptography/x509/oid.py
+++ b/src/cryptography/x509/oid.py
@@ -94,14 +94,6 @@
     INVALIDITY_DATE = ObjectIdentifier("2.5.29.24")
 
 
-CRLExtensionOID = utils.deprecated(
-    CRLEntryExtensionOID,
-    __name__,
-    "CRLExtensionOID has been renamed to CRLEntryExtensionOID",
-    utils.DeprecatedIn12
-)
-
-
 class NameOID(object):
     COMMON_NAME = ObjectIdentifier("2.5.4.3")
     COUNTRY_NAME = ObjectIdentifier("2.5.4.6")