PHSetProtocol(): negotiate PTS also for the backup protocol

If the first call to IFDSetPTS() fails with IFD_PROTOCOL_NOT_SUPPORTED
or IFD_ERROR_NOT_SUPPORTED and another protocol can be negotiated then
we call IFDSetPTS() with this second/backup protocol instead of doing
nothing.

This allows the driver to correctly configure the reader with the
selected protocol.

This happens if a card supports both T=0 and T=1, the application uses
SCARD_PROTOCOL_ANY but the reader only supports T=0.
1. The first protocol tried is T=1 (preferred over T=0).
2. If the T=1 PTS negotiation fails then we try T=0.
3. If the T=0 PTS negotiation fails then we report an error.

The step 3 was missing.

src/prothandler.c

@@ -104,6 +104,7 @@ DWORD PHSetProtocol(struct ReaderContext * rContext,
 			/* App wants unsupported protocol */
 			return SET_PROTOCOL_WRONG_ARGUMENT;
 
+again:
 	Log2(PCSC_LOG_INFO, "Attempting PTS to T=%d",
 		(SCARD_PROTOCOL_T0 == ucChosen ? 0 : 1));
 	rv = IFDSetPTS(rContext, ucChosen, 0x00, 0x00, 0x00, 0x00);
@@ -124,6 +125,14 @@ DWORD PHSetProtocol(struct ReaderContext * rContext,
 					Log3(PCSC_LOG_INFO,
 						"Set PTS failed (%ld). Using T=%d", rv,
 						(SCARD_PROTOCOL_T0 == protocol) ? 0 : 1);
+
+					/* try again with the other protocol */
+					ucChosen = protocol;
+
+					/* but no other protocol should be tried after that */
+					dwPreferred = protocol;
+
+					goto again;
 				}
 				else
 				{