(maint) specs moving from integration to unit

There were specs in integration that did not need to be located over in the
integration specs, so those were moved over to unit.
(maint) make refresh_sd optional for get_security_descriptor()
(PUP-844) Use SID when system returns non-existing user

Prior to this the system was returning identity=>"" for a non-existing user. As
this does not evaluate to nil it was causing a non-empty error during validation
instead of setting it to the SID properly.
(maint) updating comments
(PUP-847) Manage owner

This sets owner on the security descriptor. This also sets in checks to be sure
the user account exists prior to application of the user on the sd.owner.
(PUP-847) owner_to_s should not show as ''

When the actual owner account doesn't exist, show the value instead of the
fully qualified value.
(PUP-848) Manage inherit_parent_permissions

This provides the ability to manage the protect bit on security descriptors for
file paths.
(PUP-845) Invalid target should fail gracefully

This provides a nice error when the file target path doesn't exist. Prior to
this the message may not have lead a user to know it was due to trying to get a
security descriptor on an invalid target.
(PUP-1737) permissions_to_s should not return ''

Prior to this if a user did not exist, getting the FQDN account name would have
returned ''. This attempt to get the FQDN with a fallback to just return the
value. This is seen when a user you are attempting to get doesn't exist.
(PUP-1737) Confirm identities exist

This checks to be sure that each of the identities specified in the manifest
exist prior to setting permissions. If one or more accounts do not exist, this
raises an error letting the user know that the users don't exist.