patch 7.4.1753

Problem:    "noinsert" in 'completeopt' is sometimes ignored.
Solution:   Set the variables when the 'completeopt' was set. (Ozaki Kiichi)

src/option.c

@@ -6951,6 +6951,8 @@ did_set_string_option(
     {
 	if (check_opt_strings(p_cot, p_cot_values, TRUE) != OK)
 	    errmsg = e_invarg;
+	else
+	    completeopt_was_set();
     }
 #endif /* FEAT_INS_EXPAND */