Update git submodules

* Update docs/submodules/netconf from branch 'master'
  to f4584a42e889abc2d7dfaef5b16f673c02353fc9
  - Clean up NetconfHelloMessage

    - do not invoke toString() during message checking
    - use UntrustedXML directly to instantiate documents
    - use Optional.fromNullable()
    - Invert equality calls, making sure we invoke them on constants
    - eliminate the need to catch DocumentedException

    Change-Id: I6bb2165cc7b0644c5236e4c5967b03915d978e3d
    Signed-off-by: Robert Varga <robert.varga@pantheon.tech>

diff --git a/docs/submodules/netconf b/docs/submodules/netconf
index 3c29e1d939feda48a44b557c1e5c948053fc5ac8..f4584a42e889abc2d7dfaef5b16f673c02353fc9 160000 (submodule)
--- a/docs/submodules/netconf
+++ b/docs/submodules/netconf
@@ -1 +1 @@
-Subproject commit 3c29e1d939feda48a44b557c1e5c948053fc5ac8
+Subproject commit f4584a42e889abc2d7dfaef5b16f673c02353fc9