Fix memory leak of ssl_ext_host_name

ssl_ext_set_host_name uses strdup() to set a hostname into the ssl_ext
structure, but this memory was not being freed in ssl_ext_free.

Add a one-liner to free it during the ssl_ext_free routine, fixing the leak.

ssl/tls1.c

@@ -159,6 +159,8 @@ EXP_FUNC void STDCALL ssl_ext_free(SSL_EXTENSIONS *ssl_ext)
         return;
     }
 
+    free(ssl_ext->host_name); // strdup()'d in ssl_ext_set_host_name()
+
     free(ssl_ext);
 }