Implementation of host_metrics.get_all, PIF_metrics.get_all, and docs and

bindings for many of the get_all methods elsewhere that Xend already
implemented.

Signed-off-by: Ewan Mellor <ewan@xensource.com>

tools/python/xen/xend/XendAPI.py

@@ -807,6 +807,9 @@ class XendAPI(object):
     host_metrics_attr_rw = []
     host_metrics_methods = []
 
+    def host_metrics_get_all(self, _):
+        return xen_api_success([XendNode.instance().host_metrics_uuid])
+
     def _host_metrics_get(self, ref, f):
         return xen_api_success(getattr(node, f)())
 
@@ -971,6 +974,9 @@ class XendAPI(object):
     PIF_metrics_attr_rw = []
     PIF_methods = []
 
+    def PIF_metrics_get_all(self, _):
+        return xen_api_success(XendNode.instance().pif_metrics.keys())
+
     def _PIF_metrics_get(self, ref):
         return XendNode.instance().pif_metrics[ref]