Make bossrush's bomb drop probability the same as in invaders

I _think_ this is the same as in LCM.

bossrush.cpp

@@ -185,7 +185,7 @@ int main(int argc,char** argv)
 			mvaddch(boss1.y+j,boss1.x+boss1.width-1,' ');
 		}
 		boss1.next_pos();
-		if((double)rand()/RAND_MAX<shootrate*10.)		
+		if((double)rand()/RAND_MAX<shootrate*25.)
 			boss1.shoot(bombs);