Thrift: Make default values for base types work in Java.

Thrift: Make default values for base types work in Java.

Summary:
The Java generator wasn't setting default values for base types
in the zero argument constructor.  This check was probably brought over
from the C++ generator, where base types are given their default values
in the member variable initializer list (or whatever that thing is called).

Blame Rev: Somewhere in the mysterious past.  I tried to find it, but failed.

Reviewed By: mcslee

Test Plan: Recompiled Thrift and thrifted a file that showed the bug.

Revert Plan: ok

Other Notes:
Bug reported by Jake Luciani.

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665398 13f79535-47bb-0310-9956-ffa450edef68