This commit adds a couple of suppressions for known issues that valgrind
finds in libcap, and then makes a significant change to how the test
suite deals with any valgrind errors (in --enable-valgrind mode) that
are outside of these suppressions. That is, any new valgrind errors
that are discovered will cause the test that triggers them to fail.
Previous to this commit, the final valgrind "flagged functions" test
attmpted to do this by comparing valgrind output across test runs. This
worked well enough for a while, but this latest commit enforces a
stricter stance for valgrind validation of the fwknop code base.
Running the test suite with --enable-valgrind resulted in large numbers
of leaks detected in gpgme functions. This commit adds a valgrind
suppressions file to squash these errors (which are not fwknop's fault),
and also enables the valgrind --child-slient-after-fork option by
default. Both of these can disable in test suite execution with two
new options: --valgrind-disable-suppressions and
--valgrind-disable-child-silent.
