rpc: Remove unused return type from appendCommand

src/rpc/server.cpp

@@ -261,13 +261,11 @@ CRPCTable::CRPCTable()
     }
 }
 
-bool CRPCTable::appendCommand(const std::string& name, const CRPCCommand* pcmd)
+void CRPCTable::appendCommand(const std::string& name, const CRPCCommand* pcmd)
 {
-    if (IsRPCRunning())
-        return false;
+    CHECK_NONFATAL(!IsRPCRunning()); // Only add commands before rpc is running
 
     mapCommands[name].push_back(pcmd);
-    return true;
 }
 
 bool CRPCTable::removeCommand(const std::string& name, const CRPCCommand* pcmd)

src/rpc/server.h

@@ -160,7 +160,7 @@ public:
     /**
      * Appends a CRPCCommand to the dispatch table.
      *
-     * Returns false if RPC server is already running (dump concurrency protection).
+     * Precondition: RPC server is not running
      *
      * Commands with different method names but the same unique_id will
      * be considered aliases, and only the first registered method name will
@@ -169,7 +169,7 @@ public:
      * between calls based on method name, and aliased commands can also
      * register different names, types, and numbers of parameters.
      */
-    bool appendCommand(const std::string& name, const CRPCCommand* pcmd);
+    void appendCommand(const std::string& name, const CRPCCommand* pcmd);
     bool removeCommand(const std::string& name, const CRPCCommand* pcmd);
 };