isoinfo: Add default value for ignore_list paramter

ignore_list parameter was added to avoid displaying duplicated results during
deep scan.
So isoinfo main program must be updated accordingly or it will raise the
following error:

$ python kimchi/isoinfo.py http://localhost/Fedora-Live-Desktop-x86_64-19-1.iso
Traceback (most recent call last):
  File "kimchi/isoinfo.py", line 343, in <module>
    probe_iso(None, dict(path=sys.argv[1], updater=updater))
  File "kimchi/isoinfo.py", line 283, in probe_iso
    ignore_list = params['ignore_list']
KeyError: 'ignore_list'

Signed-off-by: Aline Manera <alinefm@br.ibm.com>
isoinfo: Use absolute path only for local ISO files

When running isoinfo main program to probe a remote ISO file, it returned a
wrong path:

$ python kimchi/isoinfo.py http://localhost/Fedora-Live-Desktop-x86_64-19-1.iso
[{'path': '/home/alinefm/kimchi/src/http:/localhost/Fedora-Live-Desktop-x86_64-19-1.iso',
'version': '19', 'distro': 'fedora'}]

So verify the ISO is a local one and only use abspath() in this case.
Otherwise, use the path entried by user.

Signed-off-by: Aline Manera <alinefm@br.ibm.com>
Move IsoFormatError() from isoinfo.py to exception.py

All Kimchi exception should be in exception.py
So move IsoFormatError() to there and update imports accordingly.

Signed-off-by: Aline Manera <alinefm@br.ibm.com>
Move ISO path validation to IsoImage()

That way we will have a single point to check ISO path validation.
And the user doesn't need to care about it as IsoImage() will check if the ISO
path is local, remote or invalid.

Signed-off-by: Aline Manera <alinefm@br.ibm.com>
isoinfo: Move _probe_iso() to IsoImage()

That way all operations related to IsoImage() object will be in this class.

Signed-off-by: Aline Manera <alinefm@br.ibm.com>
pep8 cleanup for isoinfo.py

This patch cleans up pep8 style issue in isoinfo.py

Signed-off-by: Aline Manera <alinefm@br.ibm.com>