IFDHSetProtocolParameters: get convention before using it

In case the reader defines CCID_CLASS_AUTO_PPS_PROP i.e. 25% or readers
according to https://ccid.apdu.fr/select_readers/?dwFeatures=6 AND the
card ATR declares ATR_CONVENTION_INVERSE i.e. 6% of cards according to
https://ludovicrousseau.blogspot.com/2016/02/atr-statistics-ts-initial-character.html
then the parameters settings were wrong.

Thanks to Coverity for the bug report:
CID 1503362 (#2 of 2): Uninitialized scalar variable (UNINIT)15.
uninit_use: Using uninitialized value convention.

src/ifdhandler.c

@@ -980,16 +980,16 @@ EXTERNAL RESPONSECODE IFDHSetProtocolParameters(DWORD Lun, DWORD Protocol,
  }
  }
 
- /* Now we must set the reader parameters */
- if (ATR_MALFORMED == ATR_GetConvention(&atr, &convention))
- return IFD_COMMUNICATION_ERROR;
-
  /* specific mode and implicit parameters? (b5 of TA2) */
  if (atr.ib[1][ATR_INTERFACE_BYTE_TA].present
  && (atr.ib[1][ATR_INTERFACE_BYTE_TA].value & 0x10))
  return IFD_COMMUNICATION_ERROR;
 
 end:
+ /* Now we must set the reader parameters */
+ if (ATR_MALFORMED == ATR_GetConvention(&atr, &convention))
+ return IFD_COMMUNICATION_ERROR;
+
  /* T=1 */
  if (SCARD_PROTOCOL_T1 == Protocol)
  {