Fix lint issue in Test/…/THH.hs

Sorry!

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

htest/Test/Ganeti/THH.hs

@@ -46,7 +46,7 @@ import Test.Ganeti.TestCommon
 -- | Type used to test optional field implementation. Equivalent to
 -- @data TestObj = TestObj { tobjA :: Maybe Int, tobjB :: Maybe Int
 -- }@.
-$(buildObject "TestObj" "tobj" $
+$(buildObject "TestObj" "tobj"
   [ optionalField $ simpleField "a" [t| Int |]
   , optionalNullSerField $ simpleField "b" [t| Int |]
   ])