This is a manual forward-port if the following change in icehouse
branch: https://review.openstack.org/211866
Object server never closes file descriptor when DiskFile.open()
raises an exception. This is fixed by catching exceptions thrown
by code block inside DiskFile.open() and manually closing the
file descriptor.
Change-Id: Ie3e047443f4893e21b9cbdea691867f069363d7e
Signed-off-by: Prashanth Pai <ppai@redhat.com>