Update git submodules

* Update docs/submodules/compass4nfv from branch 'master'
  - Install PBR to ensure we're not breaking builds

    Change-Id: I4e7b47a8f2021a1cf25b80d7818f4dabb441c39f
    Signed-off-by: wutianwei <wutianwei1@huawei.com>

diff --git a/docs/submodules/compass4nfv b/docs/submodules/compass4nfv
index 5dc83b5..4ce9351 160000 (submodule)
--- a/docs/submodules/compass4nfv
+++ b/docs/submodules/compass4nfv
@@ -1 +1 @@
-Subproject commit 5dc83b5989cc4af52bfbf2b9444ba9f28898919c
+Subproject commit 4ce9351a4802a1bdaecdf1a0fe982e2878755c03