Update DirCache Warning

When DirCache is disabled tor 0.3.1.x says:

[warn] DirCache is disabled and we are configured as a relay. This may disqualify us from becoming a guard in the future.

Since TorBrowser ships tor 0.3.1.x we can consider this as granted (not in the future), right?

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information