Description of problem:

An unfortunate typo in a error handler cause an AttriuteError when handling
an error to remove a volume run link (e.g. /run/vdsm/sd/img/vol):

I'm getting in VDSM:
2016-12-15 05:01:50,098 INFO  (merge/7adfae6f) [storage.StorageDomainManifest] Unlinking volme runtime link: u'/var/run/vdsm/storage/95e01177-20bf-4240-8656-3774e22deda0/1440299f-e24f-4d12-a6ba-ee583de8ed58/fae82f50-2d2c-406d-a293-c1f05125dc20' (blockSD:911)
2016-12-15 05:01:50,098 ERROR (merge/7adfae6f) [root] Unhandled exception (utils:369)
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/vdsm/utils.py", line 366, in wrapper
    return f(*a, **kw)
  File "/usr/share/vdsm/virt/vm.py", line 5000, in run
    self.teardown_top_volume()
  File "/usr/share/vdsm/virt/vm.py", line 4988, in teardown_top_volume
    self.job['topVolume'])
  File "/usr/share/vdsm/storage/blockSD.py", line 903, in teardownVolume
    self.removeVolumeRunLink(imgUUID, volUUID)
  File "/usr/share/vdsm/storage/blockSD.py", line 915, in removeVolumeRunLink
    if e.error != errno.ENOENT:
AttributeError: 'exceptions.OSError' object has no attribute 'error'
2016-12-15 05:01:50,098 ERROR (merge/7adfae6f) [root] Unhandled exception (utils:369)
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/vdsm/utils.py", line 366, in wrapper
    return f(*a, **kw)
  File "/usr/lib/python2.7/site-packages/vdsm/concurrent.py", line 180, in run
    return func(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/vdsm/utils.py", line 366, in wrapper
    return f(*a, **kw)
  File "/usr/share/vdsm/virt/vm.py", line 5000, in run
    self.teardown_top_volume()
  File "/usr/share/vdsm/virt/vm.py", line 4988, in teardown_top_volume
    self.job['topVolume'])
  File "/usr/share/vdsm/storage/blockSD.py", line 903, in teardownVolume
    self.removeVolumeRunLink(imgUUID, volUUID)
  File "/usr/share/vdsm/storage/blockSD.py", line 915, in removeVolumeRunLink
    if e.error != errno.ENOENT:
AttributeError: 'exceptions.OSError' object has no attribute 'error'


Version-Release number of selected component (if applicable):
vdsm-4.18.999-1162.gite95442e.el7.centos.x86_64


How reproducible:
Unknown, see once few month after the code was introduced.

Steps to Reproduce:
Unknown

Actual results:
Getting AttributeError about the wrong name.

Expected results:

1. If the link does not exists, nothing, this is expected condition. The only way
   to test for this condition correctly is to remove the link and check if 
   the operation failed with ENOENT.

2. If the link cannot be remove, fail loudly. This is unexpected situation that
   should never happen.

This is likely an expected condition (no link), but it may hide serious errors.