ob-haskell evaluation needs inf-haskell but it does not exist

[stardiviner <numbchild@gmail.com>]

When I execute the following Haskell src block:

```

#+BEGIN_SRC haskell :session :tangle "Data/Code/hello_world.hs"
main :: IO ()
main = do
  putStrLn "Hello, World!"
#+END_SRC
```

It reports error:

```

Debugger entered--Lisp error: (file-missing "Cannot open load file" "No
such file or directory" "inf-haskell")
  require(inf-haskell)
  org-babel-haskell-initiate-session(nil ((:colname-names)
(:rowname-names) (:result-params "replace") (:result-type . value)
(:results . "replace") (:exports . "code") (:cache . "no") (:noweb .
"no") (:hlines . "no") (:padlines . "no") (:session) (:tangle .
"Data/Code/hello_world.hs")))
  org-babel-execute:haskell("main :: IO ()\nmain = do\n  putStrLn
\"Hello, World!\"" ((:colname-names) (:rowname-names) (:result-params
"replace") (:result-type . value) (:results . "replace") (:exports .
"code") (:cache . "no") (:noweb . "no") (:hlines . "no") (:padlines .
"no") (:session) (:tangle . "Data/Code/hello_world.hs")))
  org-babel-execute-src-block(nil ("haskell" "main :: IO ()\nmain =
do\n  putStrLn \"Hello, World!\"" ((:colname-names) (:rowname-names)
(:result-params "replace") (:result-type . value) (:results . "replace")
(:exports . "code") (:tangle . "Data/Code/hello_world.hs") (:session)
(:padlines . "no") (:hlines . "no") (:noweb . "no") (:cache . "no")) ""
nil 1127 "(ref:%s)"))
  org-ctrl-c-ctrl-c(nil)
  funcall-interactively(org-ctrl-c-ctrl-c nil)
  call-interactively(org-ctrl-c-ctrl-c nil nil)
  command-execute(org-ctrl-c-ctrl-c)
```