Comment 10 for bug 1242435

It seems the kernel already does a fine job on setting an appropriate owner for /proc/<pid>/stat, so instead of querying the /proc/pid directory (which is owned by the user for the "ping" case), this changes the query to /proc/<pid>/stat. This patch also adds two new tests, one for "setuid and keeps privileges" (which is already working, and the much more important case), and for "setuid and drops privileges" (which is this bug, and slightly less important).

This patch is against trunk, and applies as-is (except the NEWS hunk) to raring, saucy, and trusty.