Restrict values only to allowed in cluster template

[yatin]

Currently Generic values are allowed for some of the parameters in baymodel/cluster template but these do not work:-
server_type is set to StingType as follows:
server_type = wsme.wsattr(wtypes.StringType(min_length=1,
                                                max_length=255),
                              default='vm')

1) It should be Enum('vm', 'bm') : vm for virtual machine and bm for baremetal.

2) Also api validation should be set for this so that user get proper error message if they tries to set server_type apart from allowed types('vm','bm').

Other info: There are other parameters like: volume_driver/network_driver which are set to StringType but they are validated at the time of creation.
So changing Type of these parameter to Enum doesn't seem to be required because with time volume_driver/network_driver can evolve to newly supported driver so api validation is enough.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/369145

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/369145
Committed: https://git.openstack.org/cgit/openstack/magnum/commit/?id=745188b5efa5d95bad3a2cc17f90d44118d62436
Submitter: Jenkins
Branch: master

commit 745188b5efa5d95bad3a2cc17f90d44118d62436
Author: yatin <email address hidden>
Date: Tue Sep 13 09:58:36 2016 +0530

    Restrict server type only to vm/bm

    Currently server type can be set to any String, but it should
    be restricted to only allowed types: vm/bm.
    vm: virtual machine
    bm: baremetal
    With this patch it is restricted only to allowed types.

    Change-Id: Ifbeff8621b26702e54ad088195fddcb7c35424b2
    Closes-Bug: #1622432

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/magnum 4.0.0 release.