binder: search for receiving context pid in global namespace

BugLink: http://bugs.launchpad.net/bugs/1210149

If binder cannot find the receiving task in the sender's namespace it
will default to a null PID which thus breaks communication in our
container-based scenario. This patch extends binder to first look in the
senders namespace and if unsuccesfull search in the global namespace.

Change-Id: I83077ffac575e632c1379bd69ea84b22acc61ba4
Signed-off-by: Ricardo Mendoza <ricardo.mendoza@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

https://github.com/Christopher83/samsung-kernel-msm7x30/commit/026fcc5b0163e9d93f843c856805e2981ba5c449
https://bugs.launchpad.net/ubuntu/+source/linux-grouper/+bug/1210149