L::C::Package: Add missing "exists"

Signed-off-by: Niels Thykier <niels@thykier.net>
coll/index: The trailing slash fix requires a version bump

The changes in commit 38df05466e28ab6d08ef2e8f822f9bc570844b2e
requires a version bump of coll/index to ensure it is fixed for
already unpacked packages.

Signed-off-by: Niels Thykier <niels@thykier.net>