Fix haskell-process-load-file

### Bug
Fixes a bug in which if buffer-file-name had a space in it, a `not a
module name or a source file` error would happen.
This was caused by `:load` argument not being in quotes.

This commit quotes the argument and replaces all `"` with `\"` - just
in case you are some crazy person who uses quotes in their file names.

The patch seems to work and when I run "make check" all checks passed.

### To reproduce
Create a folder such as "99 Haskell Problems" and use `haskell-process-load-or-reload`.
In `*haskell-process-log*` buffer error like the following should appear:
```
-> :load /Users/mgoszcz2/Code/99 Haskell problems/Main.hs
<- target `/Users/mgoszcz2/Code/99' is not a module name or a source file
```

### Expected result
```
-> :load "/Users/mgoszcz2/Code/99 Haskell problems/Main.hs"
<- [1 of 1] Compiling Main             ( /Users/mgoszcz2/Code/99 Haskell problems/Main.hs, interpreted )
<- Ok, modules loaded: Main.
```