packaging: setup: enforce perms on iso domain

previously if an existing directory was specified
for using it as iso domain its ownership and access bits
where untouched.

Now ownership and access bits are enforced.

Change-Id: I3ba820073983e0c32f7e762f0e6f34753528b6e6
Bug-Url: https://bugzilla.redhat.com/1004005
Bug-Url: https://bugzilla.redhat.com/1004395
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>
packaging: setup: iso domain check on / dir

previously specifying a non existent directory with
parent directory '/' like '/ISOstorage' caused a
loop trying to get the base path issuing an error.

Now '/' is handled and it is possible to define
directories like '/ISOstorage' for iso domains

Change-Id: I0aec8d729438cc1c19ba20644aa051fb70ff615f
Related-To: https://bugzilla.redhat.com/1004005
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>