Fix small typo in OpTestDelay/duration definition

The extra space results in inaccessible names; currently GHC doesn't
flag this as an error, but I've filled an upstream bug for that
(http://hackage.haskell.org/trac/ghc/ticket/7484

).

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

htools/Ganeti/OpParams.hs

@@ -1210,7 +1210,7 @@ pAllowFailover = defaultFalse "allow_failover"
 -- | Duration parameter for 'OpTestDelay'.
 pDelayDuration :: Field
 pDelayDuration =
-  renameField "DelayDuration "$ simpleField "duration" [t| Double |]
+  renameField "DelayDuration" $ simpleField "duration" [t| Double |]
 
 -- | on_master field for 'OpTestDelay'.
 pDelayOnMaster :: Field