Remove zero special-case in BN_mod_exp_mont.
A number intended to treat the base as secret should not be branching on
whether it is zero. Test-wise, this is covered by existing tests in bnmod.txt.
@@ -356,11 +356,6 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
aa = val[0];
} else
aa = a;
- if (BN_is_zero(aa)) {
- BN_zero(rr);
- ret = 1;
- goto err;
- }
if (!bn_to_mont_fixed_top(val[0], aa, mont, ctx))
goto err; /* 1 */
