Install Guide: Fix bugs in block storage node

* Fix misspelled pvcreate command
* storage node needs cinder database password
* tgtd.conf must include cinder volume configs (rhel;centos;fedora)
* lvm filter wouldn't work with the volume used

backport: havana
Closes-Bug: #1243671
(cherry picked from commit c9249bce213d6825d507c5fe15df700e1f2a3dd6)

Change-Id: I57a95cab59e3341fb74a99d5947fe54b906e32e1
Merge "Install Guide: Fix bugs in block storage node" into stable/havana