DeferErrors implies DeferTypedHoles in GHC >= 7.10

The Opt_DeferErrors flag should imply Opt_DeferTypedHoles. The proper
API for setting these flags that implements such implications is
unfortunately not exposed by GHC.

Language/Haskell/GhcMod/CaseSplit.hs

@@ -47,7 +47,7 @@ splits :: IOish m
        -> Int          -- ^ Column number.
        -> GhcModT m String
 splits file lineNo colNo =
-  ghandle handler $ runGmlT' [Left file] deferErrorsAndHoles $ do
+  ghandle handler $ runGmlT' [Left file] deferErrors $ do
       opt <- options
       crdl <- cradle
       style <- getStyle