cloud/shepherd: rename shepherd.State to shepherd.Availability

Change-Id: I8e1fa243317bf4f97af98303b10b979b98943156
Reviewed-on: https://review.monogon.dev/c/monogon/+/2779
Reviewed-by: Serge Bazanski <serge@monogon.tech>
Tested-by: Jenkins CI
diff --git a/cloud/shepherd/provider/equinix/provider.go b/cloud/shepherd/provider/equinix/provider.go
index 7d3c0d2..22cf8fa 100644
--- a/cloud/shepherd/provider/equinix/provider.go
+++ b/cloud/shepherd/provider/equinix/provider.go
@@ -139,8 +139,8 @@
 	return netip.Addr{}
 }
 
-func (e reservation) State() shepherd.State {
-	return shepherd.StateKnownUnused
+func (e reservation) Availability() shepherd.Availability {
+	return shepherd.AvailabilityKnownUnused
 }
 
 type machine struct {
@@ -148,7 +148,7 @@
 }
 
 func (e *machine) Failed() bool {
-	return e.Device.State == "failed"
+	return e.State == "failed"
 }
 
 func (e *machine) ID() shepherd.ProviderID {
@@ -177,8 +177,8 @@
 	return a
 }
 
-func (e *machine) State() shepherd.State {
-	return shepherd.StateKnownUsed
+func (e *machine) Availability() shepherd.Availability {
+	return shepherd.AvailabilityKnownUsed
 }
 
 // listReservations doesn't lock the mutex and expects the caller to lock.