Update git submodules

* Update docs/submodules/aaf/certservice.git from branch 'master'
  to d5aa15227f0c8a8bd57b668fdc25eb3935be81c5
  - Fix PrivateKey encoding in certservice-client, refactor CsrFactory

    Add PrivateKeyToPemEncoder with tests
    Refactor CsrFactory to return not encoded PEM string (less responsibility and easier to test later)

    Issue-ID: AAF-996
    Change-Id: Ia8124d43ef7fb8b1d3077c98929c52f30b6512c6
    Signed-off-by: Remigiusz Janeczek <remigiusz.janeczek@nokia.com>

diff --git a/docs/submodules/aaf/certservice.git b/docs/submodules/aaf/certservice.git
index 1d535a1..d5aa152 160000 (submodule)
--- a/docs/submodules/aaf/certservice.git
+++ b/docs/submodules/aaf/certservice.git
@@ -1 +1 @@
-Subproject commit 1d535a1b38e26c7035db2bde7405261d97bf7261
+Subproject commit d5aa15227f0c8a8bd57b668fdc25eb3935be81c5