Add supported file system type check at virt layer

Currently nova doesn't check whether the file system type is supported
by virt layer(hypervisor) before use it. This patch adds current
support file system type definition then create a default check
function at virt layer. Following patches will do the real check
in different driver such as libvirt.

Change-Id: Ie4d876a48b36c1a53b171dd521bdeef868a31486
Partial-Bug: #1293880
Merge "Add supported file system type check at virt layer"