libtls: Don't send TLS close notifies in EAP after application succeeds

With the introduction of PT-TLS, we started sending TLS close notifies after
the application layer completes (7bbf7aa9). While this makes sense for TCP based
transports, it is not required in EAP methods. In EAP, handshake completion
can be directly signaled using the outer EAP-SUCCESS message. This also saves
one round-trip in the EAP exchange.

Windows 7/8 does not seem to like TLS close notifies at all in EAP, and either
stalls (EAP-TTLS) or disconnects (PEAP).

Fixes #556.

src/libtls/tls_fragmentation.h

@@ -80,9 +80,11 @@ struct tls_fragmentation_t {
  * @param handshake			upper layer handshake protocol
  * @param alert				TLS alert handler
  * @param application		upper layer application data or NULL
+ * @param purpose			type of context this TLS stack is running in
  * @return					TLS fragmentation layer
  */
 tls_fragmentation_t *tls_fragmentation_create(tls_handshake_t *handshake,
-							tls_alert_t *alert, tls_application_t *application);
+							tls_alert_t *alert, tls_application_t *application,
+							tls_purpose_t purpose);
 
 #endif /** TLS_FRAGMENTATION_H_ @}*/