storage: Add specific check for LUKS encryption support
storage: Add specific check for LUKS encryption support

Modify virStorageBackendLogicalLVCreate to ensure if encryption
is requested that only type LUKS is supported; otherwise, error.

Signed-off-by: John Ferlan <87558058f6f829e5ec976c8ef960720af4ff9c7d@redhat.com>
Reviewed-by: Erik Skultety <2c14d38fa47c8799f1b9c16280abe27f8edfec6e@redhat.com>

crobinso/libvirt,jfehlig/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,zippy2/libvirt,fabianfreyer/libvirt,eskultety/libvirt,fabianfreyer/libvirt,crobinso/libvirt,olafhering/libvirt,libvirt/libvirt,jfehlig/libvirt,andreabolognani/libvirt,libvirt/libvirt,jardasgit/libvirt,andreabolognani/libvirt,jfehlig/libvirt,eskultety/libvirt,zippy2/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,crobinso/libvirt,crobinso/libvirt,zippy2/libvirt,jfehlig/libvirt,eskultety/libvirt,libvirt/libvirt,eskultety/libvirt,jardasgit/libvirt,nertpinx/libvirt,nertpinx/libvirt,jardasgit/libvirt,nertpinx/libvirt,olafhering/libvirt,eskultety/libvirt,olafhering/libvirt,nertpinx/libvirt,zippy2/libvirt,libvirt/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,nertpinx/libvirt,olafhering/libvirt,jardasgit/libvirt,fabianfreyer/libvirt