pkg/index: do not record a keySignerAttrValue on DelAttributeClaim

Change-Id: Ib1f81fe4879de2be7d484a5a40cc6bf0449893d5
Merge "pkg/index: do not record a keySignerAttrValue on DelAttributeClaim"
localdisk: faster enumerate.

still not as fast as possible, compared to native unix tools (find, ls, etc).
but closer.

Change-Id: I0add6bd07257f04f232332079214312297ec689b