Fixed a file descriptor leak while reading file.
Fixed a file descriptor leak while reading file.

There were two early returns without closing the file
in code common to the `ReadFile` operation in the v1
Operator API and the `/files/read` endpoint.

Review: https://reviews.apache.org/r/50208/

asamerh4/mesos,yuquanshan/customizedMesos,abudnik/mesos,Gilbert88/mesos,reneploetz/mesos,zmalik/mesos,dforsyth/mesos,reneploetz/mesos,chhsia0/mesos,Aman-Jain-14/customizedMesos,Aman-Jain-14/customizedMesos,yuquanshan/customizedMesos,jpeach/mesos,abudnik/mesos,reneploetz/mesos,yuquanshan/customizedMesos,neilconway/mesos,abudnik/mesos,verizonlabs/mesos,chhsia0/mesos,kaysoky/mesos,andschwa/mesos,verizonlabs/mesos,zmalik/mesos,gsantovena/mesos,yuquanshan/customizedMesos,Gilbert88/mesos,Gilbert88/mesos,craimbert/mesos,jpeach/mesos,andschwa/mesos,craimbert/mesos,zmalik/mesos,chhsia0/mesos,zmalik/mesos,dforsyth/mesos,Gilbert88/mesos,kaysoky/mesos,verizonlabs/mesos,yuquanshan/customizedMesos,neilconway/mesos,andschwa/mesos,kaysoky/mesos,Gilbert88/mesos,neilconway/mesos,gsantovena/mesos,neilconway/mesos,verizonlabs/mesos,Aman-Jain-14/customizedMesos,reneploetz/mesos,gsantovena/mesos,jpeach/mesos,yuquanshan/customizedMesos,gsantovena/mesos,andschwa/mesos,Aman-Jain-14/customizedMesos,craimbert/mesos,asamerh4/mesos,andschwa/mesos,neilconway/mesos,chhsia0/mesos,chhsia0/mesos,gsantovena/mesos,dforsyth/mesos,yuquanshan/customizedMesos,asamerh4/mesos,asamerh4/mesos,jpeach/mesos,zmalik/mesos,craimbert/mesos,abudnik/mesos,dforsyth/mesos,verizonlabs/mesos,asamerh4/mesos,reneploetz/mesos,abudnik/mesos,zmalik/mesos,dforsyth/mesos,reneploetz/mesos,chhsia0/mesos,reneploetz/mesos,craimbert/mesos,neilconway/mesos,chhsia0/mesos,craimbert/mesos,jpeach/mesos,gsantovena/mesos,zmalik/mesos,kaysoky/mesos,verizonlabs/mesos,dforsyth/mesos,gsantovena/mesos,kaysoky/mesos,craimbert/mesos,jpeach/mesos,asamerh4/mesos,neilconway/mesos,asamerh4/mesos,dforsyth/mesos,jpeach/mesos,Aman-Jain-14/customizedMesos,Aman-Jain-14/customizedMesos,kaysoky/mesos,kaysoky/mesos,abudnik/mesos,abudnik/mesos,Gilbert88/mesos,Gilbert88/mesos,andschwa/mesos,Aman-Jain-14/customizedMesos,andschwa/mesos,verizonlabs/mesos