Fix: crm_simulate: Prevent segfault on arches with 64bit time_t

on an s390x system:

 Program terminated with signal SIGSEGV, Segmentation fault.
 #0  ha_set_tm_time (source=0x0, target=0xb188f960) at iso8601.c:1004
 1004        if (source->tm_year > 0) {
 (gdb) bt
 #0  ha_set_tm_time (source=0x0, target=0xb188f960) at iso8601.c:1004
 ClusterLabs#1  crm_time_set_timet (target=0xb188f960, source=source@entry=0x3ffffa670a0) at iso8601.c:1037
 #2  0x0000000080004f26 in get_date (data_set=0x3ffffa67218, data_set=0x3ffffa67218) at crm_simulate.c:72
 #3  0x0000000080003d20 in main (argc=<optimized out>, argv=0x3ffffa67538) at crm_simulate.c:789

This commit fixes the cast in get_date() which would result in incorrect
values for arches with 64bit time_t

tools/crm_simulate.c

@@ -59,8 +59,11 @@ char *use_date = NULL;
 static void
 get_date(pe_working_set_t * data_set)
 {
+    int value = 0;
     time_t original_date = 0;
-    crm_element_value_int(data_set->input, "execution-date", (int*)&original_date);
+
+    crm_element_value_int(data_set->input, "execution-date", &value);
+    original_date = value;
 
     if (use_date) {
         data_set->now = crm_time_new(use_date);