ie.
    void f(void);
becomes
    void f();

I used the following command to make the changes:

  git grep -lP '\(\s*void\s*\)' -- *.cxx \
    | xargs perl -pi -w -e 's/(\w+)\s*\(\s*void\s*\)/$1\(\)/g;'

and ran it for both .cxx and .hxx files.

Change-Id: I314a1b56e9c14d10726e32841736b0ad5eef8ddd