cli: Add more nil checking to service pretty-printer

Currently, if the service mode is not "global", this code assumes that
Replicated is non-nil. This assumption may not be true in the future.
Instead of making the assumption, explicitly check that Replicated is
non-nil before using it.

Similarly, for limits and reservations, enclose methods that read from
Limits and Reservations within checks that those fields are non-nil.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

cli/command/formatter/service.go

@@ -21,7 +21,7 @@ Labels:
 {{- end }}{{ end }}
 Mode:
 {{- if .IsModeGlobal }}		Global
-{{- else }}		Replicated
+{{- else if .IsModeReplicated }}		Replicated
 {{- if .ModeReplicatedReplicas }}
  Replicas:	{{ .ModeReplicatedReplicas }}
 {{- end }}{{ end }}
@@ -73,22 +73,20 @@ Mounts:
 Resources:
 {{- if .HasResourceReservations }}
  Reservations:
-{{- end }}
 {{- if gt .ResourceReservationNanoCPUs 0.0 }}
   CPU:		{{ .ResourceReservationNanoCPUs }}
 {{- end }}
 {{- if .ResourceReservationMemory }}
   Memory:	{{ .ResourceReservationMemory }}
-{{- end }}
+{{- end }}{{ end }}
 {{- if .HasResourceLimits }}
  Limits:
-{{- end }}
 {{- if gt .ResourceLimitsNanoCPUs 0.0 }}
   CPU:		{{ .ResourceLimitsNanoCPUs }}
 {{- end }}
 {{- if .ResourceLimitMemory }}
   Memory:	{{ .ResourceLimitMemory }}
-{{- end }}{{ end }}
+{{- end }}{{ end }}{{ end }}
 {{- if .Networks }}
 Networks:
 {{- range $network := .Networks }} {{ $network }}{{ end }} {{ end }}
@@ -156,6 +154,10 @@ func (ctx *serviceInspectContext) IsModeGlobal() bool {
 	return ctx.Service.Spec.Mode.Global != nil
 }
 
+func (ctx *serviceInspectContext) IsModeReplicated() bool {
+	return ctx.Service.Spec.Mode.Replicated != nil
+}
+
 func (ctx *serviceInspectContext) ModeReplicatedReplicas() *uint64 {
 	return ctx.Service.Spec.Mode.Replicated.Replicas
 }