Fix "make distcheck".

I had forgotten to include the fuzz_static_testcases.sh script in
EXTRA_DIST.

src/test/include.am

@@ -271,6 +271,7 @@ src_test_test_bt_cl_CPPFLAGS= $(src_test_AM_CPPFLAGS) $(TEST_CPPFLAGS)
 EXTRA_DIST += \
 	src/test/bt_test.py \
 	src/test/ntor_ref.py \
+	src/test/fuzz_static_testcases.sh \
 	src/test/slownacl_curve25519.py \
 	src/test/zero_length_keys.sh \
 	src/test/test_keygen.sh \