msi: Don't ignore the error returned by ready_media.

dlls/msi/files.c

@@ -782,7 +782,6 @@ UINT ACTION_InstallFiles(MSIPACKAGE *package)
             if (rc != ERROR_SUCCESS)
             {
                 ERR("Failed to ready media\n");
-                rc = ERROR_FUNCTION_FAILED;
                 break;
             }
 

dlls/msi/tests/install.c

@@ -3548,9 +3548,9 @@ static void test_missingcab(void)
     create_pf("msitest\\gaius", TRUE);
 
     r = MsiInstallProductA(msifile, "GAIUS=1");
+    ok(r == ERROR_INSTALL_FAILURE, "Expected ERROR_INSTALL_FAILURE, got %u\n", r);
     todo_wine
     {
-        ok(r == ERROR_INSTALL_FAILURE, "Expected ERROR_INSTALL_FAILURE, got %u\n", r);
         ok(!delete_pf("msitest\\maximus", TRUE), "File installed\n");
         ok(!delete_pf("msitest\\augustus", TRUE), "File installed\n");
     }