Update default opam commands to newest syntax

Newer versions of opam don't do argument parsing of the first argument
after `opam config exec` so everything needs to be passed as separate
arguments in the shell (i.e. unquoted).

modules/prelude-ocaml.el

@@ -75,7 +75,7 @@
                                 (define-key tuareg-mode-map (kbd "C-c C-s")
                                   'utop)
                                 (setq compile-command
-                                      "opam config exec \"corebuild \""))))
+                                      "opam config exec corebuild "))))
 
 ;; Setup merlin completions company is used by default in prelude
 (add-to-list 'company-backends 'merlin-company-backend)
@@ -84,7 +84,7 @@
 ;; to activate it.
 ;; (setq merlin-use-auto-complete-mode t)
 
-(setq utop-command "opam config exec \"utop -emacs\""
+(setq utop-command "opam config exec utop -- -emacs"
       merlin-error-after-save nil)
 
 (provide 'prelude-ocaml)