flip default cookie pref to reject foreign cookies. relanding of bug 324397.

browser/app/profile/firefox.js

@@ -340,7 +340,7 @@ pref("privacy.sanitize.promptOnSanitize", true);
 
 pref("network.proxy.share_proxy_settings",  false); // use the same proxy settings for all protocols
 
-pref("network.cookie.cookieBehavior",       0); // cookies enabled
+pref("network.cookie.cookieBehavior",       1); // 0-Accept, 1-dontAcceptForeign, 2-dontUse
 pref("network.cookie.enableForCurrentSessionOnly", false);
 
 // l12n and i18n