dev-haskell/fgl: remove unused patch(es)

Signed-off-by: Michael Mair-Keimberger <mmk@levelnine.at>
Signed-off-by: Ulrich Müller <ulm@gentoo.org>

dev-haskell/fgl/files/fgl-5.6.0.0-ghc-8.6.patch

@@ -1,42 +0,0 @@
-commit 344a7e452630ace0f5c647e525e0299d99de5902
-Author: Alex Washburn <github@recursion.ninja>
-Date:   Mon Aug 20 23:46:32 2018 -0400
-
-    Fixing issue with MonadFailDesugaring.
-
-diff --git a/Data/Graph/Inductive/Monad.hs b/Data/Graph/Inductive/Monad.hs
-index 1d58af0..d63752b 100644
---- a/Data/Graph/Inductive/Monad.hs
-+++ b/Data/Graph/Inductive/Monad.hs
-@@ -1,4 +1,4 @@
--{-# LANGUAGE MultiParamTypeClasses #-}
-+{-# LANGUAGE CPP, MultiParamTypeClasses #-}
- 
- -- (c) 2002 by Martin Erwig [see file COPYRIGHT]
- -- | Monadic Graphs
-@@ -19,6 +19,10 @@ module Data.Graph.Inductive.Monad(
- 
- 
- import Data.Graph.Inductive.Graph
-+#if MIN_VERSION_base(4,12,0)
-+import Control.Monad.Fail
-+import Prelude hiding (fail)
-+#endif
- 
- {-# ANN module "HLint: ignore Redundant lambda" #-}
- 
-@@ -39,7 +43,13 @@ import Data.Graph.Inductive.Graph
- 
- -- Monadic Graph
- --
--class (Monad m) => GraphM m gr where
-+class
-+#if MIN_VERSION_base(4,12,0)
-+ (MonadFail m)
-+#else
-+ (Monad m)
-+#endif
-+  => GraphM m gr where
-   {-# MINIMAL emptyM, isEmptyM, matchM, mkGraphM, labNodesM #-}
- 
-   emptyM     :: m (gr a b)