Fix default_address()

src/gtest/test_keystore.cpp

@@ -9,6 +9,7 @@
 
 TEST(keystore_tests, sapling_keys) {
     auto sk = libzcash::SaplingSpendingKey::random();
+    auto addr = sk.default_address();
         
     // Check that full viewing key derived from sk and expanded sk are the same
     auto exp_sk = sk.expanded_spending_key();