Description of problem:
When some objects lack the field, `oc get -o=custom-columns` exits with error and has no any object output
For better UX, it should still work and is suggested to display <no value> or empty for the lacked field in those objects

Version-Release number of selected component (if applicable):
oc v3.7.0-0.175.0

How reproducible:
Always

Steps to Reproduce:
Note, below just use clusterserviceclass as example. In fact, can use any resource type to reproduce the issue, as long as some objects have but some others lack the field
1. Check objects with concerned columns
1) 2 columns
$ oc get clusterserviceclass -o=custom-columns="name:.metadata.name,display name:spec.externalMetadata.displayName"

2) Add a third concerned column, which is lacked in some object
$ oc get clusterserviceclass -o=custom-columns="name:.metadata.name,display name:spec.externalMetadata.displayName,provider:spec.externalMetadata.providerDisplayName"

3) As comparison, run above "2)" command only upon one object that does have all concerned columns
$ oc get clusterserviceclass ba4d24f1-b7c2-11e7-8556-fa163e25cbb7 -o=custom-columns="name:.metadata.name,display name:spec.externalMetadata.displayName,provider:spec.externalMetadata.providerDisplayName"

2. As comparison with above "2)", run another approach for columns
$ oc get clusterserviceclass --template="{{range .items}}{{.metadata.name}}       {{.spec.externalMetadata.displayName}}       {{.spec.externalMetadata.providerDisplayName}}
{{end}}" # note, before {{end}}, has a newline

Actual results:
1.
1) It succeeds and outputs:
name                                     display name
ba4d24f1-b7c2-11e7-8556-fa163e25cbb7     CakePHP + MySQL (Persistent)
ba6393fe-b7c2-11e7-8556-fa163e25cbb7     Pipeline Build Example
ba655233-b7c2-11e7-8556-fa163e25cbb7     MongoDB (Persistent)
...snipped other objects...

2) When some object (here, "Pipeline Build Example") lacks the field, it does not output any object, it fails and outputs:
error: providerDisplayName is not found

3) It succeeds

2. Instead of fails, it succeeds and has placeholder "<no value>":
ba4d24f1-b7c2-11e7-8556-fa163e25cbb7       CakePHP + MySQL (Persistent)       Red Hat, Inc.
ba6393fe-b7c2-11e7-8556-fa163e25cbb7       Pipeline Build Example       <no value>
ba655233-b7c2-11e7-8556-fa163e25cbb7       MongoDB (Persistent)       Red Hat, Inc.
...snipped other objects...

Expected results:
1.2: for better UX, it should be like step 2, i.e. still work when hitting objects lacking the field. It can display <no value> or empty for these objects lacked field

Additional info: