[multipath] fix early exit for blacklisted scope-limiting-device
[multipath] fix early exit for blacklisted scope-limiting-device

we tried to compare conf->dev to the blacklist entries, but entries are
usually of the {sda,sdb,...} form and conf->dev of the /dev/sda form.
No chance of succes !

This was noticed following a related behaviour reported by Maxim Kozover

xa-s05:~/scm/multipath-tools-0.4.6# multipath/multipath /dev/ram0 -v3
ram0 blacklisted

... now that early enough.

unakatsuo/multipath-tools,unakatsuo/multipath-tools,grzn/multipath-tools-explained,vijaychauhan/multipath-tools,vijaychauhan/multipath-tools,unakatsuo/multipath-tools,gebi/multipath-tools,grzn/multipath-tools-explained