core: simplify iso path validation on run vm

Simplified the iso path validation code that is being executed on run VM
by extracting the code that iterate over the images in the iso domain
looking for the floppy/disk path to separate method, and reduce the
number of nested levels and redundant fields in it.

Change-Id: I7c1734497fdb22093ec507243ef1ae6bc5006220
Signed-off-by: Arik Hadas <ahadas@redhat.com>
core: simplify boot sequence validation on run vm

Simplified the boot sequence validation code that is being executed on
run VM by reducing the number of nested levels in it.

This patch also contains additional minor refactorings: inline fields
and remove unnecessary call to "booleanValue" method.

Change-Id: I456ce87acb67ad9d9e2de988088c3ff0c7463d46
Signed-off-by: Arik Hadas <ahadas@redhat.com>
core: adjust validators on run vm for HA vm

Change the validators which check that the storage pool is up and the
VM images are valid on run VM such that they will always return
ValidationResult.Valid for HA (auto started) VM.

This change makes it possible to start HA VM when there is no SPM
defined.

Change-Id: I9db34952306bbd62e93501399ddfcf1548cfc4ed
Signed-off-by: Arik Hadas <ahadas@redhat.com>