autotest/virt-test — pull request #1284 by lmr (2013-12-20 15:41:37+00:00)
Title: virt.storage: Fix bug when checking for backup directory

By default, .get() on a dict will return None. Using None
in a os.path related function is going to throw an error.

So we can fix that issue by using an appropriate default
value that won't break os.path.isabs().

Signed-off-by: Lucas Meneghel Rodrigues