Update git submodules

* Update neutron-lib from branch 'master'
  to 28a372841402381245d65cca79c171074c4f5d21
  - Fix tap_mirror extension name in KNOWN_EXTENSIONS

    Previously it was mistakenly written as tap_mirrors

    TrivialFix

    Closes-Bug: #2136729

    Change-Id: I9973070452c866df1a995f2b92d635cf11b4c205
    Signed-off-by: Elvira Garcia <egarciar@redhat.com>

diff --git a/neutron-lib b/neutron-lib
index 87d67dd3a93c208e8d2c7efb4e7c28942008a7ce..28a372841402381245d65cca79c171074c4f5d21 160000 (submodule)
--- a/neutron-lib
+++ b/neutron-lib
@@ -1 +1 @@
-Subproject commit 87d67dd3a93c208e8d2c7efb4e7c28942008a7ce
+Subproject commit 28a372841402381245d65cca79c171074c4f5d21