Work around problem with broken workspace files.

[olsonanl]

A user had several workspace files that had bad state shock = 1 but shocknode had no node id. This results in an enumeration of all visible shock nodes followed by a crash due to unexpected format of the returned data. This PR works around the problem.

Bad workspace obj: bogus shock node $VAR1 = {
'owner' => 'gwillsey@patricbrc.org',
'shocknode' => 'https://p3.theseed.org/services/shock_api/node/',
'_id' => bless( {
'value' => '570dacc0fc65212743549e0a'
}, 'MongoDB::OID' ),
'name' => 'MERO_75_R1.fq.gz',
'shock' => 1,
'path' => '',
'autometadata' => {},
'uuid' => '2FAAC09A-011E-11E6-81D4-2FC1682E0674',
'size' => 0,
'folder' => 0,
'wsobj' => {
'owner' => 'gwillsey@patricbrc.org',
'global_permission' => 'n',
'creation_date' => '2016-03-21T17:35:49',
'permissions' => {},
'_id' => bless( {
'value' => '56f030f5fc65211d38481f2c'
}, 'MongoDB::OID' ),
'name' => 'home',
'metadata' => {},
'uuid' => '5A26A1EE-EF8B-11E5-A5FE-24B7682E0674'
},
'creation_date' => '2016-04-13T02:19:44',
'type' => 'reads',
'metadata' => {},
'workspace_uuid' => '5A26A1EE-EF8B-11E5-A5FE-24B7682E0674'
};