Remove extra semicolon at end of namespace

Upcoming clang update to r328903 adds a new warning:
  warning: extra ';' outside of a function is incompatible with C++98
  [-Wc++98-compat-extra-semi]

which is included in -Weverything.

We can just delete the extra semicolon (even though we use gnu99), and
save the extra byte.

Test: Build

Change-Id: I49b6e6af483e011632e6a34c0663c93e5c385aa6