Moved cinder::volume::iscsi out of main template

In recent puppet-cinder we cannot have two volume declarations
in single manifest. This patch removes iscsi declaration to separate
template.

Change-Id: Ie46e92ca69a674fe475d3d7303dc6ecdb8e7e1a9
Fixes: rhbz#1106512
Merge "Moved cinder::volume::iscsi out of main template"