Test on OpenSSL 1.1.0 with travis. Fixes #524 (#526)

diff --git a/src/OpenSSL/SSL.py b/src/OpenSSL/SSL.py
index 2d76516..7ebf7e0 100644
--- a/src/OpenSSL/SSL.py
+++ b/src/OpenSSL/SSL.py
@@ -109,10 +109,11 @@
 SSL_ST_CONNECT = _lib.SSL_ST_CONNECT
 SSL_ST_ACCEPT = _lib.SSL_ST_ACCEPT
 SSL_ST_MASK = _lib.SSL_ST_MASK
-SSL_ST_INIT = _lib.SSL_ST_INIT
-SSL_ST_BEFORE = _lib.SSL_ST_BEFORE
-SSL_ST_OK = _lib.SSL_ST_OK
-SSL_ST_RENEGOTIATE = _lib.SSL_ST_RENEGOTIATE
+if _lib.Cryptography_HAS_SSL_ST:
+    SSL_ST_INIT = _lib.SSL_ST_INIT
+    SSL_ST_BEFORE = _lib.SSL_ST_BEFORE
+    SSL_ST_OK = _lib.SSL_ST_OK
+    SSL_ST_RENEGOTIATE = _lib.SSL_ST_RENEGOTIATE
 
 SSL_CB_LOOP = _lib.SSL_CB_LOOP
 SSL_CB_EXIT = _lib.SSL_CB_EXIT
@@ -1160,9 +1161,10 @@
                         errno = _ffi.getwinerror()[0]
                     else:
                         errno = _ffi.errno
-                    raise SysCallError(errno, errorcode.get(errno))
-                else:
-                    raise SysCallError(-1, "Unexpected EOF")
+
+                    if errno != 0:
+                        raise SysCallError(errno, errorcode.get(errno))
+                raise SysCallError(-1, "Unexpected EOF")
             else:
                 # TODO: This is untested.
                 _raise_current_error()