PARQUET-245: Only run tests in Travis CI if build succeeds.
PARQUET-245: Only run tests in Travis CI if build succeeds.

Author: Ryan Blue <blue@apache.org>

Closes #167 from rdblue/PARQUET-245-fix-travis-ci and squashes the following commits:

ccdb0b1 [Ryan Blue] PARQUET-245: Add retry to Travis CI to fix maven downloads.
f1bb713 [Ryan Blue] PARQUET-245: Only run tests in Travis CI if build succeeds.

saucam/incubator-parquet-mr,piyushnarang/parquet-mr,nitin2goyal/parquet-mr-1,sircodesalotOfTheRound/parquet-mr,SinghAsDev/parquet-mr,rdblue/parquet-mr,spena/parquet-mr,nezihyigitbasi-nflx/parquet-mr,DataDog/parquet-mr,MickDavies/incubator-parquet-mr,cchang738/parquet-mr,coughman/incubator-parquet-mr,SinghAsDev/parquet-mr,HyukjinKwon/parquet-mr-1,sworisbreathing/parquet-mr,saucam/incubator-parquet-mr,HyukjinKwon/parquet-mr,Zariel/parquet-mr,SaintBacchus/parquet-mr,Zariel/parquet-mr,SaintBacchus/parquet-mr,rdblue/parquet-mr,MickDavies/incubator-parquet-mr,coughman/incubator-parquet-mr,HyukjinKwon/parquet-mr-1,MickDavies/incubator-parquet-mr,sircodesalotOfTheRound/parquet-mr,nguyenvanthan/parquet-mr,spena/parquet-mr,nitin2goyal/parquet-mr-1,zhenxiao/parquet-mr,zhenxiao/parquet-mr,DataDog/parquet-mr,sircodesalotOfTheRound/parquet-mr,apache/parquet-mr,laurentgo/parquet-mr,zhenxiao/parquet-mr,coughman/incubator-parquet-mr,SinghAsDev/parquet-mr,apache/parquet-mr,Zariel/parquet-mr,winningsix/incubator-parquet-mr,nguyenvanthan/parquet-mr,winningsix/incubator-parquet-mr,HyukjinKwon/parquet-mr-1,saucam/incubator-parquet-mr,DataDog/parquet-mr,piyushnarang/parquet-mr,nitin2goyal/parquet-mr-1,sworisbreathing/parquet-mr,nezihyigitbasi-nflx/parquet-mr,jaltekruse/parquet-mr-1,apache/parquet-mr,laurentgo/parquet-mr,piyushnarang/parquet-mr,sworisbreathing/parquet-mr,laurentgo/parquet-mr,jaltekruse/parquet-mr-1,HyukjinKwon/parquet-mr,rdblue/parquet-mr,cchang738/parquet-mr,nguyenvanthan/parquet-mr,nezihyigitbasi-nflx/parquet-mr,SaintBacchus/parquet-mr,cchang738/parquet-mr,jaltekruse/parquet-mr-1,spena/parquet-mr,winningsix/incubator-parquet-mr,HyukjinKwon/parquet-mr