[paging] Increase the time used to send paging messages to the BTS

Send a Paging Request to the BTS every two seconds. This way it is
unlikely that a phone will try to respond to two paging requests as
it is currently happening.
diff --git a/openbsc/src/paging.c b/openbsc/src/paging.c
index 7c3750d..9c978be 100644
--- a/openbsc/src/paging.c
+++ b/openbsc/src/paging.c
@@ -160,7 +160,7 @@
 	} while (paging_bts->available_slots > 0
 		    &&  initial_request != current_request);
 
-	bsc_schedule_timer(&paging_bts->work_timer, 1, 0);
+	bsc_schedule_timer(&paging_bts->work_timer, 2, 0);
 }
 
 static void paging_worker(void *data)
@@ -245,7 +245,7 @@
 	llist_add_tail(&req->entry, &bts_entry->pending_requests);
 
 	if (!bsc_timer_pending(&bts_entry->work_timer))
-		bsc_schedule_timer(&bts_entry->work_timer, 1, 0);
+		bsc_schedule_timer(&bts_entry->work_timer, 2, 0);
 
 	return 0;
 }