Fix travis build error, old apr downloads not found
```
$ wget http://ftp.jaist.ac.jp/pub/apache/apr/${APR}.tar.gz
2017-10-26 09:33:48--
Resolving ftp.jaist.ac.jp (ftp.jaist.ac.jp)... 150.65.7.130, 2001:df0:2ed:feed::feed
Connecting to ftp.jaist.ac.jp (ftp.jaist.ac.jp)|150.65.7.130|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2017-10-26 09:33:49 ERROR 404: Not Found.
```
@@ -57,8 +57,8 @@ install:
## ----------------------------------------------------------------------
env:
- - APR=apr-1.6.2
- APR_UTIL=apr-util-1.6.0
+ - APR=apr-1.6.3
+ APR_UTIL=apr-util-1.6.1
before_script:
- export PATH=${TRAVIS_BUILD_DIR}/tools/bin:$PATH
