MXSession: Add logs to track if E2EE is enabled by default on the current HS.

Riot/Categories/MXSession+Riot.m

@@ -65,6 +65,7 @@
     }
     else
     {
+        MXLogInfo(@"[MXSession] E2EE is disabled by default on this homeserver");
         success(NO);
         return [MXHTTPOperation new];
     }