Fix pointer arithmetic instead of concat

`"my number " + 5` does not produces `"my number 5"` but rather `"mber "`.
If the number was greater than `len(string) + 2`
(pointing to the \0 and one past the end in authorized, more in UB)
the result would have been undefined behaviour.

Transforme the number to std::string using toString.

Signed-off-by: Kevin Rocard <[email protected]>

Author: krocard

parameter/Subsystem.cpp

@@ -440,7 +440,7 @@ bool CSubsystem::handleSubsystemObjectCreation(
                 pSubsystemObjectCreator->getMaxConfigurableElementSize()) {
 
                 string strSizeError = "Size should not exceed " +
-                                      pSubsystemObjectCreator->getMaxConfigurableElementSize();
+                                      toString(pSubsystemObjectCreator->getMaxConfigurableElementSize());
 
                 strError = getMappingError(strKey, strSizeError, pInstanceConfigurableElement);