Change the Cryptography-specific variable names
diff --git a/cryptography/hazmat/backends/openssl/ssl.py b/cryptography/hazmat/backends/openssl/ssl.py
index 7e7de5c..76bb836 100644
--- a/cryptography/hazmat/backends/openssl/ssl.py
+++ b/cryptography/hazmat/backends/openssl/ssl.py
@@ -17,10 +17,10 @@
TYPES = """
/* Internally invented symbol to tell us if SSLv2 is supported */
-static const int Cryptography_NO_SSL2;
+static const int Cryptography_HAS_SSL2;
/* Internally invented symbol to tell us if SNI is supported */
-static const int Cryptography_TLSEXT_HOSTNAME;
+static const int Cryptography_HAS_TLSEXT_HOSTNAME;
static const int SSL_FILETYPE_PEM;
static const int SSL_FILETYPE_ASN1;
@@ -244,18 +244,18 @@
CUSTOMIZATIONS = """
#ifdef OPENSSL_NO_SSL2
-static const int Cryptography_NO_SSL2 = 1;
+static const int Cryptography_HAS_SSL2 = 0;
SSL_METHOD* (*SSLv2_method)() = NULL;
SSL_METHOD* (*SSLv2_client_method)() = NULL;
SSL_METHOD* (*SSLv2_server_method)() = NULL;
#else
-static const int Cryptography_NO_SSL2 = 0;
+static const int Cryptography_HAS_SSL2 = 1;
#endif
#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
-static const int Cryptography_TLSEXT_HOSTNAME = 1;
+static const int Cryptography_HAS_TLSEXT_HOSTNAME = 1;
#else
-static const int Cryptography_TLSEXT_HOSTNAME = 0;
+static const int Cryptography_HAS_TLSEXT_HOSTNAME = 0;
void (*SSL_set_tlsext_host_name)(SSL *, char *) = NULL;
const char* (*SSL_get_servername)(const SSL *, const int) = NULL;
void (*SSL_CTX_set_tlsext_servername_callback)(