Change deploy validation exception handling

Calls to the deploy validate() method may throw an InvalidParameterValue
exception during node deploy or node tear down. It's more logical to catch
this and throw an InstanceDeployFailure exception instead.

This addresses comments raised during review of change ID
Ic3107a9af6afeb2a9e772ca0ce0acc45dbc182cb.

The test_do_node_deploy_validate_fail and test_do_node_tear_down_validate_fail
tests intentionally still have their mocked object raise the
InvalidParameterValue exception to test that it gets transformed into
an InstanceDeployFailure exception.

Change-Id: I754884d1a012a9e67d2cc7a74e3121e0e02e76ec
Merge "Change deploy validation exception handling"