NTLM single-sign on adjustments (XI)

Feature string literal NTLM_SSO renamed to NTLM_WB.
Preprocessor symbol USE_NTLM_SSO renamed to WINBIND_NTLM_AUTH_ENABLED.
curl's 'long' option 'ntlm-sso' renamed to 'ntlm-wb'.
Fix some comments to make clear that this is actually a NTLM delegation.

configure.ac

@@ -2996,7 +2996,7 @@ if test "x$CURL_DISABLE_HTTP" != "x1"; then
       -o "x$GNUTLS_ENABLED" = "x1" -o "x$NSS_ENABLED" = "x1"; then
     SUPPORT_FEATURES="$SUPPORT_FEATURES NTLM"
     if test "x$WINBIND_NTLM_AUTH_ENABLED" = "x1"; then
-      SUPPORT_FEATURES="$SUPPORT_FEATURES NTLM_SSO"
+      SUPPORT_FEATURES="$SUPPORT_FEATURES NTLM_WB"
     fi
   fi
 fi