Correct path reference to bits path hit by ULS

Follows change Id362b24ab. I nested the cache-control configuration directives
in the existing <Directory> block, but it appears not to exist. Add a separate
<Directory> block for the actual file path hit by ULS font reuqests.

Change-Id: I1113b959490c3db279e9ea1414e8e599f2f99d32
Merge "Correct path reference to bits path hit by ULS"