sysinstall: suppress 'no' prompt to begin installation

The user has to type 'yes', but it doesn't mean that the default of
'no' is ever useful. Suppress it, so the user doesn't have to press
backspace twice.

src/cryptenroll/cryptenroll-interactive.c

@@ -151,7 +151,7 @@ static int ask_wipe(EnrollContext *c, unsigned existing_mask) {
                         return log_oom();
 
                 bool wipe;
-                r = prompt_loop_yes_no(question, /* def= */ false, &wipe);
+                r = prompt_loop_yes_no(question, "no", /* def= */ false, &wipe);
                 if (r < 0)
                         return r;