Fix for introspection

[rafalgajda-silvair]

This patch fixes the way introspection generates node structure for requested path.

Lets export more than one interface under similar path, eg.:
'/test/path'
'/test/path/child'

If a client introspects the root path '/' the response will include duplicated child node:
<node name="/">
<node name="com" />
<node name="com" />
</node>"

Client recursively asking and building interface tree will cause n^2 visible service interfaces where n is a number of actual service interfaces exported.
This patch fixes this behavior (test case included)

[acrisci]

👍