On read we already ignore bad values, so we shouldn't be restricting
this on write; doing so alters expected data-in-data-out behavior. In
addition, don't issue a warning if a given `ttl` value can't be parsed,
as this can quickly get annoying if it's on purpose.
The documentation has been updated/clarified to make it clear that this
is optional behavior that doesn't affect the status of the key as POD
and the `lease_duration` returned will otherwise default to the
system/mount defaults.
Fixes#1505
This commit splits ACL policies into more fine-grained capabilities.
This both drastically simplifies the checking code and makes it possible
to support needed workflows that are not possible with the previous
method. It is backwards compatible; policies containing a "policy"
string are simply converted to a set of capabilities matching previous
behavior.
Fixes#724 (and others).
