pipeline: include mounts in stage checksum

When calculating the checksum of the stage, the mount options were
not included. This was maybe deliberate, because if the mounts of
a stage change, it is very likely that previous stages change too.
But the introduction of non-device mounts, like ostree.deployment,
have changed the setting, since the content of the tree will be
different if that mount is applied or not. And even for the device
based mounts it will change the tree if e.g. a device is mounted
at at different path but otherwise is formatted with the very same
options. In the worst case we miss a few cache hits due to changes
in the mount setup that don't lead to tree changes, but that will
rarely happen in practice.

osbuild/pipeline.py

@@ -88,6 +88,9 @@ class Stage:
         if self.inputs:
             data = {n: i.id for n, i in self.inputs.items()}
             m.update(json.dumps(data, sort_keys=True).encode())
+        if self.mounts:
+            data = [m.id for m in self.mounts.values()]
+            m.update(json.dumps(data).encode())
         return m.hexdigest()
 
     @property