Deep scan: Fix isoinfo.py for iso can't be reported

In b1d5002d we add glob for all iso files under directory,
but a directory name without a slash at the end won't get right result.
(try: python isoinfo.py /an-iso-directory-without-trailing-slash )
Fix it by using absolute path.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
Deep scan: Update API.md

Add a 'kimchi-iso' type pool for deep scan,
with path of which refers to scan targeted path.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
Deep scan: update controller

For API performs asynchronous POST requests,
returning resource with 202,
'task_id' of async task id generated for this request
for future user polling.

Add storage pool type of task_id,
this field is reported when storagepool is a deep scan
generated pool.

REF:
https://access.redhat.com/site/documentation/en-US/ \
     Red_Hat_Enterprise_Virtualization/3.0/ \
     html-single/REST_API_Guide/ \
     index.html#sect-REST_API_Guide-Common_Features-Resources-Creating_Resources

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
Deep scan: Add functions for deep scan preparation

Prepare the temp directory for pool and create then symlink,
implement the scan logic with probe_iso.
pool timeout check will be done when a new scan request is issued,
timeout scan result clean includes clean storage pool,
directory and db entries.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
deep scan: add model support

Use libvirt transient pool to create iso pool,
because they are active when created,
and destroyed when libvirt stops, which are suitable for iso pools.
Scanned pool will not survive kimchid restart,
their remainings will be cleaned at start up.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>