scripts/oss-fuzz: ignore the generic-fuzz target

scripts/oss-fuzz: ignore the generic-fuzz target

generic-fuzz is not a standalone fuzzer - it requires some env variables
to be set. On oss-fuzz, we set these with some predefined
generic-fuzz-{...} targets, that are thin wrappers around generic-fuzz.
Do not make a link for the generic-fuzz from the oss-fuzz build, so
oss-fuzz does not treat it as a standalone fuzzer.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201023150746.107063-18-alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
[thuth: Reformatted one comment to stay within the 80 columns limit]
Signed-off-by: Thomas Huth <thuth@redhat.com>