1203: remove TLS fallback-limit

Currently enforcing the default at 3, it gets changed to 4 for FF62, and will get deprecated some stage soon - https://bugzilla.mozilla.org/show_bug.cgi?id=1479501

user.js

@@ -701,7 +701,6 @@ user_pref("_user.js.parrot", "1200 syntax error: the parrot's a stiff!");
  * [2] https://www.ssl.com/how-to/turn-off-ssl-3-0-and-tls-1-0-in-your-browser/
  * [2] archived: https://archive.is/hY2Mm ***/
 user_pref("security.tls.version.min", 3);
-user_pref("security.tls.version.fallback-limit", 3);
 user_pref("security.tls.version.max", 4); // 4 = allow up to and including TLS 1.3
 /* 1203: disable SSL session tracking (FF36+)
  * SSL Session IDs speed up HTTPS connections (no need to renegotiate) and last for 48hrs.