Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to 2df391a041a85a0187a5eaad082d3a8f2fbaeaec
  - Merge "Handle when model cust uuid is null from sdnc"
  - Handle when model cust uuid is null from sdnc
    
    Modify wording on null uuid exception and test for it
    Expand null handling to vfmc and cvnfc find in lists
    Modify to chain the filter of nulls then to match.
    Change to ExpectedException in junit; filter nulls.
    Handle better when model cust. uuid is null from sdnc
    
    Change-Id: I1f1edffa1db84509bd649803660a55510868b6eb
    Issue-ID: SO-1989
    Signed-off-by: Benjamin, Max (mb388a) <mb388a@us.att.com>
    
diff --git a/docs/submodules/so.git b/docs/submodules/so.git
index 83bd49d..2df391a 160000
--- a/docs/submodules/so.git
+++ b/docs/submodules/so.git
@@ -1 +1 @@
-Subproject commit 83bd49d1f3576be61173b426fc899d687f9f34fa
+Subproject commit 2df391a041a85a0187a5eaad082d3a8f2fbaeaec