Possible fix for srep64 v393a data corruption - need more testing

[elit]

Just a quick note, last night I tried to pack ~30gb again, I used standard shipped exe not the one self-recompiled I posted here. However this time I tried with acceleration disabled: a0. And it did packed properly. I will post again after some time and more data tests on whether this option really solved the problem or not.(Btw increasing block size did not.)