doc: Fix Texinfo docs; remove krb4 references

doc/setup.texi

@@ -84,11 +84,9 @@ are briefly described here.
 The @samp{libdefaults} section contains a list of library configuration
 parameters, such as the default realm and the timeout for KDC
 responses. The @samp{realms} section contains information about specific
-realms, such as where they hide their KDC@. This section serves the same
-purpose as the Kerberos 4 @file{krb.conf} file, but can contain more
-information. Finally the @samp{domain_realm} section contains a list of
-mappings from domains to realms, equivalent to the Kerberos 4
-@file{krb.realms} file.
+realms, such as where they hide their KDC@.
+Finally the @samp{domain_realm} section contains a list of
+mappings from domains to realms.
 
 To continue with the realm setup, you will have to create a configuration file,
 with contents similar to the following.
@@ -674,10 +672,6 @@ fixed size encryption key.
 In Kerberos 5 the salt is determined by the encryption type, except in
 some special cases.
 
-In @code{des} there is the Kerberos 4 salt
-(none at all) or the afs-salt (using the cell (realm in
-AFS lingo)).
-
 In @code{arcfour} (the encryption type that Microsoft Windows 2000 uses)
 there is no salt. This is to be compatible with NTLM keys in Windows
 NT 4.
@@ -696,12 +690,6 @@ no salt at all).
 Common types of salting include
 
 @itemize @bullet
-@item @code{v4} (or @code{des:pw-salt:})
-
-The Kerberos 4 salting is using no salt at all. Reason there is colon
-at the end of the salt string is that it makes the salt the empty
-string (same as no salt).
-
 @item @code{v5} (or @code{pw-salt})
 
 @code{pw-salt} uses the default salt for each encryption type is