add pkg recache to postinstall

Author: gbaz

hptool/os-extras/osx/installer-scripts/postinstall.mu

@@ -5,6 +5,8 @@ cd "/Library/Haskell/ghc-{{ghcVersion}}-{{arch}}/bin"
 ./activate-hs "{{ghcVersion}}-{{arch}}"
 ./uninstall-hs install-check "{{ghcVersion}}" Finder
 
+ghc-pkg recache
+
 if [ "${COMMAND_LINE_INSTALL}" == '1' ] ; then
     echo "View documentation with this command:"
     echo "    open /Library/Haskell/doc/start.html"