Wallet: Initialize members without default ctor.

Found by Coverity (188336 in Anonimal's Coverity account).

src/wallet/wallet2.cpp

@@ -902,6 +902,7 @@ wallet2::wallet2(network_type nettype, uint64_t kdf_rounds, bool unattended):
   m_multisig(false),
   m_multisig_threshold(0),
   m_node_rpc_proxy(m_http_client, m_daemon_rpc_mutex),
+  m_account_public_address{crypto::null_pkey, crypto::null_pkey},
   m_subaddress_lookahead_major(SUBADDRESS_LOOKAHEAD_MAJOR),
   m_subaddress_lookahead_minor(SUBADDRESS_LOOKAHEAD_MINOR),
   m_light_wallet(false),
@@ -918,6 +919,7 @@ wallet2::wallet2(network_type nettype, uint64_t kdf_rounds, bool unattended):
   m_last_block_reward(0),
   m_encrypt_keys_after_refresh(boost::none),
   m_unattended(unattended),
+  m_devices_registered(false),
   m_device_last_key_image_sync(0)
 {
 }