Merge pull request bitcoin#527 from comboy/bip66-dead-link

fix dead link in BIP66

Author: luke-jr

bip-0066.mediawiki

@@ -37,7 +37,7 @@ These operators all perform ECDSA verifications on pubkey/signature pairs, itera
 
 The following code specifies the behaviour of strict DER checking. Note that this function tests a signature byte vector which includes the 1-byte sighash flag that Bitcoin adds, even though that flag falls outside of the DER specification, and is unaffected by this proposal. The function is also not called for cases where the length of sig is 0, in order to provide a simple, short and efficiently-verifiable encoding for deliberately invalid signatures.
 
-DER is specified in http://www.itu.int/rec/T-REC-X.690-200811-I/en .
+DER is specified in https://www.itu.int/rec/T-REC-X.690/en .
 
 <pre>
 bool static IsValidSignatureEncoding(const std::vector<unsigned char> &sig) {