storage: lvm: use correct lv* command parameters
storage: lvm: use correct lv* command parameters

lvcreate want's the parent pool's name, not the pool path
lvchange and lvremove want lv specified as $vgname/$lvname

This largely worked before because these commands strip off a
starting /dev. But https://bugzilla.redhat.com/show_bug.cgi?id=714986
is from a user using a 'nested VG' that was having problems.

I couldn't find any info on nested LVM and the reporter never responded,
but I reproduced with XML that specified a valid source name, and
set target path to a symlink.

warewolf/libvirt,rmarwaha/libvirt1,rmarwaha/libvirt1,iam-TJ/libvirt,jfehlig/libvirt,iam-TJ/libvirt,wiedi/libvirt,zippy2/libvirt,iam-TJ/libvirt,eskultety/libvirt,rmarwaha/libvirt,foomango/libvirt,olafhering/libvirt,wiedi/libvirt,emaste/libvirt,rmarwaha/libvirt,jardasgit/libvirt,shugaoye/libvirt,cbosdo/libvirt,rmarwaha/libvirt1,fabianfreyer/libvirt,libvirt/libvirt,eskultety/libvirt,taget/libvirt,cbosdo/libvirt,siboulet/libvirt-openvz,nertpinx/libvirt,andreabolognani/libvirt,trainstack/libvirt,dumbbell/libvirt,agx/libvirt,dumbbell/libvirt,zippy2/libvirt,cbosdo/libvirt,nertpinx/libvirt,agx/libvirt,siboulet/libvirt-openvz,dumbbell/libvirt,wiedi/libvirt,agx/libvirt,rmarwaha/libvirt1,VenkatDatta/libvirt,jeckersb/libvirt,VenkatDatta/libvirt,zhlcindy/libvirt-1.1.4-maintain,novel/fbsd-libvirt,warewolf/libvirt,jeckersb/libvirt,emaste/libvirt,fabianfreyer/libvirt,eskultety/libvirt,rmarwaha/libvirt,dumbbell/libvirt,jeckersb/libvirt,fabianfreyer/libvirt,rlaager/libvirt,iam-TJ/libvirt,trainstack/libvirt,andreabolognani/libvirt,rmarwaha/libvirt,taget/libvirt,crobinso/libvirt,zhlcindy/libvirt-1.1.4-maintain,zippy2/libvirt,jeckersb/libvirt,taget/libvirt,libvirt/libvirt,novel/fbsd-libvirt,iam-TJ/libvirt,trainstack/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,VenkatDatta/libvirt,VenkatDatta/libvirt,iam-TJ/libvirt,foomango/libvirt,jardasgit/libvirt,foomango/libvirt,rlaager/libvirt,shugaoye/libvirt,emaste/libvirt,novel/fbsd-libvirt,shugaoye/libvirt,olafhering/libvirt,VenkatDatta/libvirt,libvirt/libvirt,datto/libvirt,trainstack/libvirt,emaste/libvirt,elmarco/libvirt,trainstack/libvirt,nertpinx/libvirt,bjzhang/libvirt,rmarwaha/libvirt,siboulet/libvirt-openvz,elmarco/libvirt,foomango/libvirt,warewolf/libvirt,fabianfreyer/libvirt,dumbbell/libvirt,jardasgit/libvirt,foomango/libvirt,taget/libvirt,eskultety/libvirt,datto/libvirt,andreabolognani/libvirt,elmarco/libvirt,jfehlig/libvirt,datto/libvirt,siboulet/libvirt-openvz,novel/fbsd-libvirt,shugaoye/libvirt,libvirt/libvirt,bjzhang/libvirt,taget/libvirt,rlaager/libvirt,zippy2/libvirt,andreabolognani/libvirt,wiedi/libvirt,jeckersb/libvirt,iam-TJ/libvirt,olafhering/libvirt,novel/fbsd-libvirt,warewolf/libvirt,bjzhang/libvirt,rlaager/libvirt,elmarco/libvirt,nertpinx/libvirt,elmarco/libvirt,datto/libvirt,trainstack/libvirt,shugaoye/libvirt,nertpinx/libvirt,agx/libvirt,novel/fbsd-libvirt,bjzhang/libvirt,jardasgit/libvirt,jeckersb/libvirt,dumbbell/libvirt,rmarwaha/libvirt1,siboulet/libvirt-openvz,zhlcindy/libvirt-1.1.4-maintain,agx/libvirt,warewolf/libvirt,emaste/libvirt,rlaager/libvirt,rmarwaha/libvirt,crobinso/libvirt,trainstack/libvirt,zhlcindy/libvirt-1.1.4-maintain,cbosdo/libvirt,jardasgit/libvirt,wiedi/libvirt,novel/fbsd-libvirt,cbosdo/libvirt,eskultety/libvirt,warewolf/libvirt,andreabolognani/libvirt,olafhering/libvirt,novel/fbsd-libvirt,emaste/libvirt,crobinso/libvirt,jfehlig/libvirt,wiedi/libvirt,emaste/libvirt,datto/libvirt,jeckersb/libvirt,wiedi/libvirt,crobinso/libvirt,novel/fbsd-libvirt,bjzhang/libvirt,rmarwaha/libvirt1,warewolf/libvirt,zhlcindy/libvirt-1.1.4-maintain