bn_fix_top() exists for compatibility's sake and is mapped to

bn_correct_top() or bn_check_top() depending on debug settings. For
internal source, all bn_fix_top()s should be converted one way or the other
depending on whether the use of bn_correct_top() is justified.

For BN_div_recp(), these cases should not require correction if the other
bignum functions are doing their jobs properly, so convert to
bn_check_top().

crypto/bn/bn_recp.c

@@ -204,8 +204,8 @@ int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
 	ret=1;
 err:
 	BN_CTX_end(ctx);
-	if(dv) bn_fix_top(dv);
-	if(rem) bn_fix_top(rem);
+	if(dv) bn_check_top(dv);
+	if(rem) bn_check_top(rem);
 	return(ret);
 	}