crypto: fix megacheck warnings

[egonelbre]

megacheck warnings still left:

crypto\ecies\asn1.go:50:2: var shaScheme is unused (U1000)
crypto\ecies\asn1.go:52:2: var x963Scheme is unused (U1000)
crypto\ecies\asn1.go:90:2: var rawCurveP256 is unused (U1000)
crypto\ecies\asn1.go:91:2: var rawCurveP384 is unused (U1000)
crypto\ecies\asn1.go:92:2: var rawCurveP521 is unused (U1000)
crypto\ecies\asn1.go:95:6: func rawCurve is unused (U1000)
crypto\ecies\asn1.go:171:2: var oidSHA1 is unused (U1000)
crypto\ecies\asn1.go:172:2: var oidSHA224 is unused (U1000)
crypto\ecies\asn1.go:173:2: var oidSHA256 is unused (U1000)
crypto\ecies\asn1.go:174:2: var oidSHA384 is unused (U1000)
crypto\ecies\asn1.go:175:2: var oidSHA512 is unused (U1000)
crypto\ecies\asn1.go:178:6: func hashFromOID is unused (U1000)
crypto\ecies\asn1.go:194:6: func oidFromHash is unused (U1000)
crypto\ecies\asn1.go:212:2: var asnAlgoSHA1 is unused (U1000)
crypto\ecies\asn1.go:215:2: var asnAlgoSHA224 is unused (U1000)
crypto\ecies\asn1.go:218:2: var asnAlgoSHA256 is unused (U1000)
crypto\ecies\asn1.go:221:2: var asnAlgoSHA384 is unused (U1000)
crypto\ecies\asn1.go:224:2: var asnAlgoSHA512 is unused (U1000)
crypto\ecies\asn1.go:240:6: type asnECPKAlgorithms is unused (U1000)
crypto\ecies\asn1.go:245:5: var idEcPublicKey is unused (U1000)
crypto\ecies\asn1.go:248:6: func curveToRaw is unused (U1000)
crypto\ecies\asn1.go:262:6: func asnECPublicKeyType is unused (U1000)
crypto\ecies\asn1.go:283:5: var asnECDH is unused (U1000)
crypto\ecies\asn1.go:288:2: var dhSinglePass_stdDH_sha1kdf is unused (U1000)
crypto\ecies\asn1.go:336:5: var eciesRecommendedParameters is unused (U1000)
crypto\ecies\asn1.go:337:5: var eciesSpecifiedParameters is unused (U1000)

This is the same question, what to do with specification constants that are unused?

[fjl]

I'll delete asn1.go, we don't use it.

[egonelbre]

Do the Marshal|Unmarhsal Public|Private have to be reimplemented or can they removed as well? If they can be removed then I can add commit that deletes asn1.go.