Fix Blowfish URL.

Submitted by: Arnaud De Timmerman <Arnaud.De.Timmerman@branchur.fr>

doc/crypto/blowfish.pod

@@ -28,7 +28,7 @@ BF_cfb64_encrypt, BF_ofb64_encrypt, BF_options - Blowfish encryption
 =head1 DESCRIPTION
 
 This library implements the Blowfish cipher, which is invented and described
-by Counterpane (see http://www.counterpane.com/blowfish/ ).
+by Counterpane (see http://www.counterpane.com/blowfish.html ).
 
 Blowfish is a block cipher that operates on 64 bit (8 byte) blocks of data.
 It uses a variable size key, but typically, 128 bit (16 byte) keys are