Fix a memory leak in the CarlaString class

Signed-off-by: falkTX <falktx@falktx.com>

source/utils/CarlaString.hpp

@@ -819,7 +819,7 @@ public:
         std::memcpy(newBuf, fBuffer, fBufferLen);
         std::memcpy(newBuf + fBufferLen, strBuf, strBufLen + 1);
 
-        return CarlaString(newBuf);
+        return CarlaString(newBuf, false);
     }
 
     CarlaString operator+(const CarlaString& str) noexcept