Added iSCSI multipath status to the API

In this commit the multipath status is available in the following
endpoint:
/ovirt-engine/api/hosts/xxxx/storage

A new field has been added <available_paths> that represents the
multipaths that are NOT faulty as an integer value. This is useful for monitoring (you can
compare 'available_paths' to 'paths' and trigger an alert when
'available_paths' is lower than 'paths'.

Signed-off-by: Brooklyn Dewolf <contact@brooklyn.gent>

backend/manager/modules/common/src/main/java/org/ovirt/engine/core/common/businessentities/storage/LUNs.java

@@ -269,6 +269,10 @@ public int getPathCount() {
         return getPathsDictionary() == null ? 0 : getPathsDictionary().size();
     }
 
+    public int getAvailablePathCount() {
+        return getPathsDictionary() == null ? 0 : (int) getPathsDictionary().values().stream().filter(o -> o).count();
+    }
+
     public Map<String, Boolean> getPathsDictionary() {
         return pathsDictionary;
     }

backend/manager/modules/restapi/types/src/main/java/org/ovirt/engine/api/restapi/types/StorageLogicalUnitMapper.java

@@ -58,6 +58,7 @@ public static LogicalUnit map(LUNs entity, LogicalUnit template) {
             model.setTarget(lunConnection.getIqn());
         }
 
+        model.setAvailablePaths(entity.getAvailablePathCount());
         model.setPaths(entity.getPathCount());
         return model;
     }