opensc: Buffer overflow handling responses from Cryptoflex cards in cryptoflex-tool.c:read_public_key()

Several buffer overflows when handling responses from a Cryptoflex card in readpublickey in tools/cryptoflex-tool.c in OpenSC before 0.19.0-rc1 could be used by attackers able to supply crafted smartcards to cause a denial of service application crash or possibly have unspecified other impact...