Add a brief variable glossary entry for the new PSEUDO_IGNORE_PATHS
variable.
(From yocto-docs rev: a337bb317dacdeb174397e7ee8258bc74560436b)
Signed-off-by: Paul Eggleton <paul.eggleton@microsoft.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>