Revert "PL/Python: Fix potential NULL pointer dereference"

This reverts commit e42e2f3.

It's not safe to return in the middle of a PG_TRY block, so this will
have to be done differently.

Author: petere

src/pl/plpython/plpy_spi.c

@@ -361,10 +361,7 @@ PLy_spi_execute_fetch_result(SPITupleTable *tuptable, uint64 rows, int status)
 
 	result = (PLyResultObject *) PLy_result_new();
 	if (!result)
-	{
-		SPI_freetuptable(tuptable);
 		return NULL;
-	}
 	Py_DECREF(result->status);
 	result->status = PyInt_FromLong(status);
 
@@ -417,9 +414,7 @@ PLy_spi_execute_fetch_result(SPITupleTable *tuptable, uint64 rows, int status)
 				if (!result->rows)
 				{
 					Py_DECREF(result);
-					MemoryContextDelete(cxt);
-					SPI_freetuptable(tuptable);
-					return NULL;
+					result = NULL;
 				}
 				else
 				{