netfilter: qtaguid: initialize a local var to keep compiler happy.

There was a case that might have seemed like new_tag_stat was not
initialized and actually used.
Added comment explaining why it was impossible, and a BUG()
in case the logic gets changed.

Change-Id: I1eddd1b6f754c08a3bf89f7e9427e5dce1dfb081
Signed-off-by: JP Abgrall <jpa@google.com>
p50x_defconfig: Update netfilter options

Change-Id: I0ecd4d1348eca7e712e5998be99aa565a55bceda
various: compilation fixes for gcc 4.6

These changes are required to compile successfully with
gcc version 4.6.

The -Wno-address option is applied to some files to
bypass a warning triggered by an rcu macro. The
warning is fixed cleanly upstream, but that fix is too
risky to backport, so it is better to just silence it
this way.

Change-Id: I787ad2db6e649d29874b7b624c2b28f686236466
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>