[XTM] Don't send (or remove) empty Messages.properties

When pushing to XTM connectors-ee Messages.properties, XTM raise warning on empty files:

• https://github.com/Talend/connectors-ee/blob/master/aws-common/src/main/resources/org/talend/components/aws/common/service/Messages.properties
• https://github.com/Talend/connectors-ee/blob/master/aws-common/src/main/resources/org/talend/components/aws/Messages.properties
• https://github.com/Talend/connectors-ee/blob/master/dynamodb/src/main/resources/org/talend/components/dynamodb/processor/Messages.properties
• https://github.com/Talend/connectors-ee/blob/master/neo4j/src/main/resources/org/talend/components/neo4j/processor/Messages.properties

hmassy told me:

but for empty files, XTM doesn't seem to like this and I had to "force" processing them

We should try to net send them, or to remove them if possible.