Parse out '@' in volume['host'] to do discovery
Parse out '@' in volume['host'] to do discovery

The backup method of getting iscsi info is to use
iscsiadm discovery, however currently that method
just uses volume['host'] which in the case of
multi-backend will use "host@backend-name".

This will cause the discovery to fail of course, so
this change just parses out the '@' symbol if it's present
and avoids the problem in the first place.

This also beefs up the error logging and exception catching
a bit.

Parsing out the '@' symbol all the time should be safe as
the accepted valid chars for hostnames are digits, a-z and
hyphens.

Change-Id: Ic45a38bf4c56a4aec6847ab0d29e3b41d35bd3d2
Closes-Bug: #1250673

petrutlucian94/cinder,redhat-openstack/cinder,cloudbase/cinder,sasukeh/cinder,Akrog/cinder,rakeshmi/cinder,manojhirway/ExistingImagesOnNFS,Nexenta/cinder,Paul-Ezell/cinder-1,petrutlucian94/cinder,tlakshman26/cinder-new-branch,Hybrid-Cloud/cinder,redhat-openstack/cinder,saeki-masaki/cinder,NetApp/cinder,tlakshman26/cinder-bug-fix-volume-conversion-full,abusse/cinder,sasukeh/cinder,eharney/cinder,tlakshman26/cinder-https-changes,hguemar/cinder,dims/cinder,spring-week-topos/cinder-week,scality/cinder,Datera/cinder,tlakshman26/cinder-https-changes,NetApp/cinder,hguemar/cinder,apporc/cinder,takeshineshiro/cinder,winndows/cinder,alex8866/cinder,leilihh/cinder,manojhirway/ExistingImagesOnNFS,openstack/cinder,duhzecca/cinder,nexusriot/cinder,scottdangelo/RemoveVolumeMangerLocks,duhzecca/cinder,potsmaster/cinder,CloudServer/cinder,nikesh-mahalka/cinder,Hybrid-Cloud/cinder,apporc/cinder,mahak/cinder,Thingee/cinder,j-griffith/cinder,JioCloud/cinder,potsmaster/cinder,Nexenta/cinder,bswartz/cinder,NeCTAR-RC/cinder,Paul-Ezell/cinder-1,alex8866/cinder,dims/cinder,blueboxgroup/cinder,Accelerite/cinder,scottdangelo/RemoveVolumeMangerLocks,Akrog/cinder,abusse/cinder,rakeshmi/cinder,Thingee/cinder,spring-week-topos/cinder-week,Accelerite/cinder,leilihh/cinder,julianwang/cinder,eharney/cinder,nikesh-mahalka/cinder,tlakshman26/cinder-new-branch,CloudServer/cinder,phenoxim/cinder,tlakshman26/cinder-bug-fix-volume-conversion-full,phenoxim/cinder,bswartz/cinder,mahak/cinder,saeki-masaki/cinder,openstack/cinder,cloudbase/cinder,NeCTAR-RC/cinder,takeshineshiro/cinder,JioCloud/cinder,github-borat/cinder,github-borat/cinder,blueboxgroup/cinder,nexusriot/cinder,j-griffith/cinder,julianwang/cinder,Thingee/cinder,winndows/cinder,scality/cinder,Datera/cinder,ge0rgi/cinder