Only logs missing schema warning once

[brendanjryan]

Changes the output produced by the --ignore-missing-schemas to only print Warning: Set to ignore missing schemas once per invocation instead of once per file provided.

Before:

bin/kubeval --ignore-missing-schemas fixtures/valid.yaml fixtures/valid.yaml
Warning: Set to ignore missing schemas
The file fixtures/valid.yaml contains a valid ReplicationController
Warning: Set to ignore missing schemas
The file fixtures/valid.yaml contains a valid ReplicationController

After:

bin/kubeval --ignore-missing-schemas fixtures/valid.yaml fixtures/valid.yaml 
Warning: Set to ignore missing schemas
The file fixtures/valid.yaml contains a valid ReplicationController
The file fixtures/valid.yaml contains a valid ReplicationController

[brendanjryan]

cc @garethr

[garethr]

Looks like this needs a rebase with master to merge, but thanks for the fix. I'll probably wait for this and docs for #169 and ship a new release with those in.

[brendanjryan]

Thank YOU. It should be good to go now