Add NIC VLAN field retrieval to Haskell queries

The field was added to Python queries in an earlier version, and now
has to be added to the Haskell queries as well.
Signed-off-by: Hrvoje Ribicic <riba@google.com>
Reviewed-by: Thomas Thrainer <thomasth@google.com>

src/Ganeti/Query/Instance.hs

@@ -284,6 +284,9 @@ instanceFields =
   , (fieldDefinitionCompleter "nic.link/%d" "NicLink/%d" QFTText
      ("Link" ++ nicDescSuffix),
      getIndexedNicField nicpLink, QffNormal)
+  , (fieldDefinitionCompleter "nic.vlan/%d" "NicVLAN/%d" QFTText
+     ("VLAN" ++ nicDescSuffix),
+     getOptionalIndexedNicField getNicVlan, QffNormal)
   , (fieldDefinitionCompleter "nic.network.name/%d" "NicNetworkName/%d" QFTText
      ("Network name" ++ nicDescSuffix),
      getIndexedNicNetworkNameField, QffNormal)
@@ -334,6 +337,12 @@ getNicBridge nicParams
   | nicpMode nicParams == NMBridged = Just $ nicpLink nicParams
   | otherwise                       = Nothing
 
+-- | Gets the VLAN of a NIC.
+getNicVlan :: FilledNicParams -> Maybe String
+getNicVlan params
+  | nicpMode params == NMOvs = Just $ nicpVlan params
+  | otherwise                = Nothing
+
 -- | Fill partial NIC params by using the defaults from the configuration.
 fillNicParamsFromConfig :: ConfigData -> PartialNicParams -> FilledNicParams
 fillNicParamsFromConfig cfg = fillNicParams (getDefaultNicParams cfg)