Disambiguate createLink/createSymbolicLink errors

Per the comments on PR #65, it should be unambiguous.

Author: luispedro

System/Posix/Files.hsc

@@ -228,7 +228,7 @@ createLink :: FilePath -> FilePath -> IO ()
 createLink name1 name2 =
   withFilePath name1 $ \s1 ->
   withFilePath name2 $ \s2 ->
-  throwErrnoIfMinus1_ ("createLink "++name1++" to "++name2) (c_link s1 s2)
+  throwErrnoIfMinus1_ ("createLink (target: "++name1++") (linkpath: "++name2++")") (c_symlink s1 s2)
 
 -- | @removeLink path@ removes the link named @path@.
 --
@@ -252,7 +252,7 @@ createSymbolicLink :: FilePath -> FilePath -> IO ()
 createSymbolicLink file1 file2 =
   withFilePath file1 $ \s1 ->
   withFilePath file2 $ \s2 ->
-  throwErrnoIfMinus1_ ("createSymbolicLink "++file1++" to "++file2) (c_symlink s1 s2)
+  throwErrnoIfMinus1_ ("createSymbolicLink (target: "++file1++") (linkpath: "++file2++")") (c_symlink s1 s2)
 
 foreign import ccall unsafe "symlink"
   c_symlink :: CString -> CString -> IO CInt