Following up on r1544169, reduce the amount of new java warnings by
the change to a level that allows investigating issues.

* build/ac-macros/java.m4
* build/generator/gen_win.py
  Suppress deprecation warnings.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1544226 13f79535-47bb-0310-9956-ffa450edef68
* build/generator/gen_win.py
  Following up on r1544226, really suppress the intended warnings on Windows.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1544242 13f79535-47bb-0310-9956-ffa450edef68