Update haskeline submodule to 0.7.2.1 release tag
Update haskeline submodule to 0.7.2.1 release tag

This fixes compilation under windows with pre-AMP GHCs
although it's not clear if bootstrapping GHC was affected.
(see https://github.com/judah/haskeline/issues/20 for details)

(cherry picked from commit 899cb3e768bf495b396f59dc2b49b7b10eb4ad8c)

nathyong/microghc-ghc,forked-upstream-packages-for-ghcjs/ghc,forked-upstream-packages-for-ghcjs/ghc,forked-upstream-packages-for-ghcjs/ghc,forked-upstream-packages-for-ghcjs/ghc,nathyong/microghc-ghc,forked-upstream-packages-for-ghcjs/ghc,nathyong/microghc-ghc,nathyong/microghc-ghc,nathyong/microghc-ghc,forked-upstream-packages-for-ghcjs/ghc,forked-upstream-packages-for-ghcjs/ghc,nathyong/microghc-ghc,nathyong/microghc-ghc