Add switch to choose SSH v1-versus-v2 protocol preference where both

are available

[originally from svn r584]

putty.h

@@ -139,6 +139,7 @@ typedef struct {
     int nopty;
     enum { CIPHER_3DES, CIPHER_BLOWFISH, CIPHER_DES } cipher;
     char keyfile[FILENAME_MAX];
+    int sshprot;                       /* use v1 or v2 when both available */
     int try_tis_auth;
     /* Telnet options */
     char termtype[32];