Prevent redundant commenting by drive-audit
Prevent redundant commenting by drive-audit

The drive-audit detects error log about a device and comments out it
in /etc/fstab. When the error log is generated several times, it
comments out the line for each time.
This patch makes drive-audit to check if the device is already
commented out, and prevents redundant commenting out.

Change-Id: Ia542d35b58552dde0f324bb9c42531f98c9058fa

bradleypj823/swift,clayg/swift,smerritt/swift,psachin/swift,gold3bear/swift,matthewoliver/swift,rackerlabs/swift,dpgoetz/swift,Seagate/swift,swiftstack/swift,IPVL/swift-kilo,revoer/keystone-8.0.0,smerritt/swift,tipabu/swift,openstack/swift,Em-Pan/swift,psachin/swift,wenhuizhang/swift,openstack/swift,thiagodasilva/swift,tipabu/swift,bouncestorage/swift,aerwin3/swift,larsbutler/swift,prashanthpai/swift,bkolli/swift,shibaniahegde/OpenStak_swift,notmyname/swift,notmyname/swift,iostackproject/IO-Bandwidth-Differentiation,anishnarang/gswift,maginatics/swift,mjzmjz/swift,redhat-openstack/swift,Akanoa/swift,dencaval/swift,redbo/swift,hurricanerix/swift,psachin/swift,maginatics/swift,smerritt/swift,matthewoliver/swift,zackmdavis/swift,hbhdytf/mac,mjwtom/swift,tipabu/swift,dpgoetz/swift,bkolli/swift,redbo/swift,prashanthpai/swift,thiagodasilva/swift,hbhdytf/mac,takeshineshiro/swift,redhat-openstack/swift,larsbutler/swift,matthewoliver/swift,anishnarang/gswift,nadeemsyed/swift,hurricanerix/swift,nadeemsyed/swift,williamthegrey/swift,tipabu/swift,IPVL/swift-kilo,notmyname/swift,swiftstack/swift,clayg/swift,smerritt/swift,Em-Pan/swift,AfonsoFGarcia/swift,hbhdytf/mac2,wenhuizhang/swift,psachin/swift,daasbank/swift,mjwtom/swift,matthewoliver/swift,aerwin3/swift,swiftstack/swift,nadeemsyed/swift,levythu/swift,iostackproject/IO-Bandwidth-Differentiation,clayg/swift,Seagate/swift,daasbank/swift,openstack/swift,mjzmjz/swift,williamthegrey/swift,notmyname/swift,takeshineshiro/swift,Akanoa/swift,hbhdytf/mac2,dencaval/swift,rackerlabs/swift,eatbyte/Swift,nadeemsyed/swift,eatbyte/Swift,hbhdytf/mac2,clayg/swift,bradleypj823/swift,zackmdavis/swift,shibaniahegde/OpenStak_swift,hbhdytf/mac2,bouncestorage/swift,hurricanerix/swift,revoer/keystone-8.0.0,hurricanerix/swift,AfonsoFGarcia/swift,openstack/swift,gold3bear/swift,levythu/swift