crypto/ecdsa, crypto/x509: update SEC1 ECC link in comments

Updated the document URL in comments to avoid dead link
Old: http://www.secg.org/download/aid-780/sec1-v2.pdf
New: http://www.secg.org/sec1-v2.pdf

Change-Id: If13d0da4c0e7831b2bd92c45116c2412a2a965f5
Reviewed-on: https://go-review.googlesource.com/11550Reviewed-by: Russ Cox <rsc@golang.org>

src/crypto/ecdsa/ecdsa.go

@@ -14,7 +14,7 @@ package ecdsa
 //   [NSA]: Suite B implementer's guide to FIPS 186-3,
 //     http://www.nsa.gov/ia/_files/ecdsa.pdf
 //   [SECG]: SECG, SEC1
-//     http://www.secg.org/download/aid-780/sec1-v2.pdf
+//     http://www.secg.org/sec1-v2.pdf
 
 import (
 	"crypto"

src/crypto/x509/sec1.go

@@ -18,7 +18,7 @@ const ecPrivKeyVersion = 1
 // ecPrivateKey reflects an ASN.1 Elliptic Curve Private Key Structure.
 // References:
 //   RFC5915
-//   SEC1 - http://www.secg.org/download/aid-780/sec1-v2.pdf
+//   SEC1 - http://www.secg.org/sec1-v2.pdf
 // Per RFC5915 the NamedCurveOID is marked as ASN.1 OPTIONAL, however in
 // most cases it is not.
 type ecPrivateKey struct {