Kill dead code (#647)

* Simplify code

* dead code

* unused...

* write imports normally
diff --git a/src/OpenSSL/SSL.py b/src/OpenSSL/SSL.py
index b571a5e..b17d25b 100644
--- a/src/OpenSSL/SSL.py
+++ b/src/OpenSSL/SSL.py
@@ -8,9 +8,9 @@
 
 from cryptography.utils import deprecated
 
-from six import binary_type as _binary_type
-from six import integer_types as integer_types
-from six import int2byte, indexbytes
+from six import (
+    binary_type as _binary_type, integer_types as integer_types, int2byte,
+    indexbytes)
 
 from OpenSSL._util import (
     UNSPECIFIED as _UNSPECIFIED,
@@ -59,9 +59,8 @@
 OP_NO_SSLv2 = _lib.SSL_OP_NO_SSLv2
 OP_NO_SSLv3 = _lib.SSL_OP_NO_SSLv3
 OP_NO_TLSv1 = _lib.SSL_OP_NO_TLSv1
-
-OP_NO_TLSv1_1 = getattr(_lib, "SSL_OP_NO_TLSv1_1", 0)
-OP_NO_TLSv1_2 = getattr(_lib, "SSL_OP_NO_TLSv1_2", 0)
+OP_NO_TLSv1_1 = _lib.SSL_OP_NO_TLSv1_1
+OP_NO_TLSv1_2 = _lib.SSL_OP_NO_TLSv1_2
 
 MODE_RELEASE_BUFFERS = _lib.SSL_MODE_RELEASE_BUFFERS
 
diff --git a/tests/test_ssl.py b/tests/test_ssl.py
index 1ca7f8b..5bb4451 100644
--- a/tests/test_ssl.py
+++ b/tests/test_ssl.py
@@ -66,11 +66,6 @@
     OP_NO_QUERY_MTU, OP_COOKIE_EXCHANGE, OP_NO_TICKET, OP_NO_COMPRESSION,
     MODE_RELEASE_BUFFERS)
 
-try:
-    from OpenSSL.SSL import OP_NO_TLSv1, OP_NO_TLSv1_1, OP_NO_TLSv1_2
-except ImportError:
-    OP_NO_TLSv1 = OP_NO_TLSv1_1 = OP_NO_TLSv1_2 = None
-
 from OpenSSL.SSL import (
     SSL_ST_CONNECT, SSL_ST_ACCEPT, SSL_ST_MASK,
     SSL_CB_LOOP, SSL_CB_EXIT, SSL_CB_READ, SSL_CB_WRITE, SSL_CB_ALERT,