[File Connector] No error message is provided when a file is tried to copy to a non existing destination

[isuruuy429]

Description:
It does not provide any error message and returns success=true when it provides a non-existing destination to file copy operation.

Steps to reproduce:

1. Create the following API in Integration Studio and deploy it in wso2mi-1.1.0.

<?xml version="1.0" encoding="UTF-8"?>
<api context="/connect" name="Connect" xmlns="http://ws.apache.org/ns/synapse">
   <resource methods="POST" uri-template="/copy">
        <inSequence>
            <property expression="json-eval($.source)" name="source" scope="default" type="STRING"/>
            <property expression="json-eval($.destination)" name="destination" scope="default" type="STRING"/>
            <fileconnector.copy>
                <source>{$ctx:source}</source>
                <destination>{$ctx:destination}</destination>
            </fileconnector.copy>
            <respond/>
        </inSequence>
        <outSequence/>
        <faultSequence/>
    </resource>
</api>

2. In the payload provide a valid source file and invalid location to be copied.
3. Invoke the API.

Expected: It should provide an error message as 'The destination location does not exist', and it should return success=false.
Actual: It does not provide any error and returns 'success=true' as the response.