Workaround for BN_bn2mpi reading/writing out of bounds
Workaround for BN_bn2mpi reading/writing out of bounds

When OpenSSL's BN_bn2mpi is passed a buffer of size 4, valgrind
reports reading/writing one byte past it. I am unable to find
evidence of this behaviour in BN_bn2mpi's source code, so it may
be a spurious warning. However, this change is harmless, as only
the bignum with value 0 results in an mpi serialization of size 4.

coinkeeper/2015-06-22_19-10_cannacoin,Cannacoin-Project/Cannacoin,coinkeeper/2015-06-22_19-10_cannacoin,coinkeeper/2015-06-22_19-10_cannacoin,Cannacoin-Project/Cannacoin,reddcoin-project/reddcoin,joroob/reddcoin,reddink/reddcoin,coinkeeper/2015-06-22_19-10_cannacoin,reddcoin-project/reddcoin,joroob/reddcoin,reddcoin-project/reddcoin,ahmedbodi/poscoin,Cannacoin-Project/Cannacoin,Cannacoin-Project/Cannacoin,ahmedbodi/poscoin,reddink/reddcoin,ahmedbodi/poscoin,bmp02050/ReddcoinUpdates,coinkeeper/2015-06-22_18-46_reddcoin,ahmedbodi/poscoin,bmp02050/ReddcoinUpdates,reddink/reddcoin,joroob/reddcoin,joroob/reddcoin,coinkeeper/2015-06-22_18-46_reddcoin,Cannacoin-Project/Cannacoin,coinkeeper/2015-06-22_18-46_reddcoin,ahmedbodi/poscoin,joroob/reddcoin,coinkeeper/2015-06-22_18-46_reddcoin,bmp02050/ReddcoinUpdates,reddcoin-project/reddcoin,reddcoin-project/reddcoin,bmp02050/ReddcoinUpdates,coinkeeper/2015-06-22_19-10_cannacoin,reddcoin-project/reddcoin,bmp02050/ReddcoinUpdates,reddink/reddcoin,coinkeeper/2015-06-22_18-46_reddcoin,reddink/reddcoin