Fix travis build error, old apr downloads not found
Fix travis build error, old apr downloads not found

```
$ wget http://ftp.jaist.ac.jp/pub/apache/apr/${APR}.tar.gz
--2017-10-26 09:33:48--  http://ftp.jaist.ac.jp/pub/apache/apr/apr-1.6.2.tar.gz
Resolving ftp.jaist.ac.jp (ftp.jaist.ac.jp)... 150.65.7.130, 2001:df0:2ed:feed::feed
Connecting to ftp.jaist.ac.jp (ftp.jaist.ac.jp)|150.65.7.130|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2017-10-26 09:33:49 ERROR 404: Not Found.
```

yuanzhao/gpdb,edespino/gpdb,edespino/gpdb,Chibin/gpdb,lisakowen/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,lisakowen/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,lisakowen/gpdb,greenplum-db/gpdb,lisakowen/gpdb,Chibin/gpdb,adam8157/gpdb,50wu/gpdb,Chibin/gpdb,yuanzhao/gpdb,Chibin/gpdb,50wu/gpdb,Chibin/gpdb,xinzweb/gpdb,adam8157/gpdb,adam8157/gpdb,xinzweb/gpdb,jmcatamney/gpdb,edespino/gpdb,50wu/gpdb,Chibin/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,50wu/gpdb,xinzweb/gpdb,jmcatamney/gpdb,lisakowen/gpdb,Chibin/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,adam8157/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,xinzweb/gpdb,xinzweb/gpdb,50wu/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,lisakowen/gpdb,greenplum-db/gpdb,xinzweb/gpdb,adam8157/gpdb,jmcatamney/gpdb,adam8157/gpdb,ashwinstar/gpdb,edespino/gpdb,adam8157/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,edespino/gpdb,yuanzhao/gpdb,edespino/gpdb,adam8157/gpdb,ashwinstar/gpdb,edespino/gpdb,lisakowen/gpdb,50wu/gpdb,edespino/gpdb,Chibin/gpdb,yuanzhao/gpdb,edespino/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,xinzweb/gpdb,Chibin/gpdb,50wu/gpdb,ashwinstar/gpdb,Chibin/gpdb,50wu/gpdb,xinzweb/gpdb,lisakowen/gpdb,edespino/gpdb,yuanzhao/gpdb