Fix out-of-bounds read noticed by Ricardo Correia
Fix out-of-bounds read noticed by Ricardo Correia

Sizeof() returned the size of a pointer instead of the size of the buffer.
Fixes issue #1924.

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