Plan created with only version breaks plan table

[Melissa Kam]

If a plan is created with just the version and nothing else, an invalid plan is created which causes all calls to plan to fail with 500s. The invalid plan can only be deleted by removing it from the database.

Error Responses + Stack Trace:
Your request could not be handled because of a problem in the server. Error Correlation id is: 438af5b2-dac1-4c62-9b63-b6e5717fb067'

{
    "debuginfo": null,
    "faultcode": "Server",
    "faultstring": "Could not find any element in your YAML mapping."
}

2015-05-26_20:01:50.18203 127.0.0.1 - - [26/May/2015 20:01:50] "POST /v1/plans HTTP/1.1" 201 216
2015-05-26_20:01:54.40805 2015-05-26 20:01:54.407 27382 ERROR solum.common.exception [-] Could not find any element in your YAML mapping.
2015-05-26_20:01:54.40830 2015-05-26 20:01:54.408 27382 ERROR solum.common.exception [-] abccbbfa-75c3-473f-8ba5-dc998cd5332a:Could not find any element in your YAML mapping.
2015-05-26_20:01:54.40915 127.0.0.1 - - [26/May/2015 20:01:54] "GET /v1/plans HTTP/1.1" 500 131

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/189951