Fix two bugs regarding stale SIS messages, from Kruzen

When entering Hyperspace on Auto-Pilot, or are intercepted by
neutral or hostile alien ships during Auto-Pilot, the text at the
top of the screen doesn't update properly until the status
would need to change. This corrects the times when DrawSisMessage
is called to keep that up-to-date as needed.

This patch was backported from the Mega-Mod.

sc2/src/uqm/encount.c

@@ -326,6 +326,7 @@ InitEncounter (void)
 		t.CharCount = (COUNT)~0;
 		font_DrawText (&t);
 	}
+	DrawSISMessage (NULL);
 
 	s.origin.x = SIS_SCREEN_WIDTH >> 1;
 	s.origin.y = SIS_SCREEN_HEIGHT >> 1;

sc2/src/uqm/hyper.c

@@ -349,7 +349,10 @@ LoadHyperspace (void)
 			RepairSISBorder ();
 		}
 	}
-	DrawSISMessage (NULL);
+	if (!(GLOBAL (autopilot.x) != ~0 && GLOBAL (autopilot.y) != ~0))
+	{
+		DrawSISMessage (NULL);
+	}
 
 	SetContext (RadarContext);
 	SetContextBackGroundColor (