Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to b15889d217c97f80a973e5b594dd198ce011c78c
  - Merge "Define constants in place of repeated literals Defined constants to avoid repeated use of literals Issue-ID: SO-1490 bash: c: command not found"
  - Define constants in place of repeated literals
    Defined constants to avoid repeated use of literals
    Issue-ID: SO-1490
    bash: c: command not found

    Change-Id: I6e3808fc462c9c87f5cfbe81f39aad3187b49930
    Signed-off-by: h00397475 <hena.choudhury@huawei.com>

diff --git a/docs/submodules/so.git b/docs/submodules/so.git
index 096a514..b15889d 160000 (submodule)
--- a/docs/submodules/so.git
+++ b/docs/submodules/so.git
@@ -1 +1 @@
-Subproject commit 096a5140050a7fc634f73e3587d8c202393243aa
+Subproject commit b15889d217c97f80a973e5b594dd198ce011c78c