Fix shellcheck failures SC2251

https://github.com/koalaman/shellcheck/wiki/SC2251

This may be masking some test failures.

We have a bunch of test code like this:

set -o errexit
[...]
! kubectl get pod wrong-pod
[...]

This test will succeed no matter what the result (return code) of kubectl is.

test/cmd/create.sh

@@ -50,7 +50,7 @@ run_kubectl_create_error_tests() {
   kube::log::status "Testing kubectl create with error"
 
   # Passing no arguments to create is an error
-  ! kubectl create
+  ! kubectl create || exit 1
 
   ## kubectl create should not panic on empty string lists in a template
   ERROR_FILE="${KUBE_TEMP}/validation-error"