In some cases we want to test the availability of siginfo files, in some
cases we do not and really want the .tgz files (which may or may
not be present too). This makes adds a parameter to the function to allow
this.
(From OE-Core rev: e8867b97a772f8e64fe209436c15d382b2175ca0)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>