[mutter] unit-tests: Fix const compiler warning

[Florian Müllner <fmuellner src gnome org>]

commit 868b3fd01e7b71127d61945e053d7fdf70f2e2c7
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Mar 10 17:32:42 2016 +0100

    unit-tests: Fix const compiler warning

 src/tests/unit-tests.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/tests/unit-tests.c b/src/tests/unit-tests.c
index 019b6d5..37332f0 100644
--- a/src/tests/unit-tests.c
+++ b/src/tests/unit-tests.c
@@ -213,9 +213,9 @@ main (int argc, char *argv[])
 
   g_option_context_free (ctx);
 
-  char *fake_args[] = { NULL, "--wayland", "--nested" };
+  const char *fake_args[] = { NULL, "--wayland", "--nested" };
   fake_args[0] = argv[0];
-  char **fake_argv = fake_args;
+  char **fake_argv = (char**)fake_args;
   int fake_argc = G_N_ELEMENTS (fake_args);
 
   ctx = meta_get_option_context ();