Revamp digest functions

- Hash() has been removed because it was ambiguous, Md5() and Sha0() are proper replacements.
- HMacMd5() and HMacSha1() now share a common implementation handled by the new Internal_HMac() function.
- NewMd() and MdProcess() now support plain hashing (without the key).
- NewMd(), SetMdKey() and MdProcess() now check the OpenSSL functions' return value and in case of failure a debug message is printed along with the error string, if available.
- SetMdKey()'s return value has been changed from void to bool, so that it's possible to know whether the function succeeded or not.
- MdProcess()' return value has been changed from void to UINT (unsigned int) and the function now returns the number of bytes written by HMAC_Final() or EVP_DigestFinal_ex().

src/Cedar/Proto_IKE.c

@@ -3937,7 +3937,7 @@ BUF *IkeStrToVendorId(char *str)
 		BUF *buf;
 		UCHAR hash[MD5_SIZE];
 
-		Hash(hash, str, StrLen(str), false);
+		Md5(hash, str, StrLen(str));
 
 		buf = MemToBuf(hash, sizeof(hash));