panic for invalid gcs service account

[mirshahriar]

When ServiceAccount json in osm config is in wrong format, it gives panic.

/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:72
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:65
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:51
/usr/local/go/src/runtime/asm_amd64.s:509
/usr/local/go/src/runtime/panic.go:491
/usr/local/go/src/runtime/panic.go:63
/usr/local/go/src/runtime/signal_unix.go:367
/go/src/github.com/k8sdb/elasticsearch/vendor/golang.org/x/oauth2/jwt/jwt.go:89
<autogenerated>:1
/go/src/github.com/k8sdb/elasticsearch/vendor/golang.org/x/oauth2/oauth2.go:263
/go/src/github.com/k8sdb/elasticsearch/vendor/golang.org/x/oauth2/transport.go:40
/usr/local/go/src/net/http/client.go:249
/usr/local/go/src/net/http/client.go:173
/usr/local/go/src/net/http/client.go:602
/go/src/github.com/k8sdb/elasticsearch/vendor/google.golang.org/api/gensupport/send.go:42
/go/src/github.com/k8sdb/elasticsearch/vendor/google.golang.org/api/storage/v1/storage-gen.go:2954
/go/src/github.com/k8sdb/elasticsearch/vendor/google.golang.org/api/storage/v1/storage-gen.go:2968
/go/src/github.com/k8sdb/elasticsearch/vendor/github.com/graymeta/stow/google/location.go:82
/go/src/github.com/k8sdb/elasticsearch/vendor/github.com/k8sdb/apimachinery/pkg/storage/osm.go:65
/go/src/github.com/k8sdb/elasticsearch/vendor/github.com/k8sdb/apimachinery/pkg/validator/validate.go:68
/go/src/github.com/k8sdb/elasticsearch/pkg/controller/snapshot.go:38
/go/src/github.com/k8sdb/elasticsearch/vendor/github.com/k8sdb/apimachinery/pkg/controller/snapshot.go:160
/go/src/github.com/k8sdb/elasticsearch/vendor/github.com/k8sdb/apimachinery/pkg/controller/snapshot.go:127
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/client-go/tools/cache/controller.go:195
<autogenerated>:1
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/client-go/tools/cache/controller.go:314
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/client-go/tools/cache/delta_fifo.go:451
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/client-go/tools/cache/controller.go:150
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/client-go/tools/cache/controller.go:124
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go:133
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go:134
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go:88
/go/src/github.com/k8sdb/elasticsearch/vendor/k8s.io/client-go/tools/cache/controller.go:124
/go/src/github.com/k8sdb/elasticsearch/vendor/github.com/k8sdb/apimachinery/pkg/controller/snapshot.go:141
/go/src/github.com/k8sdb/elasticsearch/vendor/github.com/k8sdb/apimachinery/pkg/controller/snapshot.go:78
/go/src/github.com/k8sdb/elasticsearch/pkg/controller/controller.go:181
/usr/local/go/src/runtime/asm_amd64.s:2337