lvm: lvm.conf (locking_type = 4)

lvm:  lvm.conf (locking_type = 4)

- the use of sed is placeholder "hack" until lvm2 provides a proper
  tool for changing lvm.conf
- lvm_scan.sh should run lvm commands with --ignorelockingfailure to
  re-use lvm's existing initrd-specific logic; future lvm2 changes
  will split this flag out into various new command-line switches
- no monitoring should be started from within initramfs
- NOTE: the same should apply to 90dmraid/install
- the correct types would be: '[ "blkext", 1 , "cciss0", 16 ]'
  but lvm2 (>= 2.02.52) already properly supports both 'blkext' and
  'cciss' (including cciss0 -> cciss7)