wallet: GetLabelAddresses requires cs_wallet lock

No change in behavior, the lock is already held at call sites.

src/wallet/wallet.cpp

@@ -2191,7 +2191,7 @@ void CWallet::MarkDestinationsDirty(const std::set<CTxDestination>& destinations
 
 std::set<CTxDestination> CWallet::GetLabelAddresses(const std::string& label) const
 {
-    LOCK(cs_wallet);
+    AssertLockHeld(cs_wallet);
     std::set<CTxDestination> result;
     for (const std::pair<const CTxDestination, CAddressBookData>& item : m_address_book)
     {

src/wallet/wallet.h

@@ -630,7 +630,7 @@ public:
 
     int64_t GetOldestKeyPoolTime() const;
 
-    std::set<CTxDestination> GetLabelAddresses(const std::string& label) const;
+    std::set<CTxDestination> GetLabelAddresses(const std::string& label) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     /**
      * Marks all outputs in each one of the destinations dirty, so their cache is