Update git submodules

* Update docs/submodules/parser from branch 'master'
  - change some doc file names

    upstream rst files kept in the project subdirectory which not meet the
    requirement of OPNFV(in docs/).

    issues in
    https://build.opnfv.org/ci/job/docs-verify-rtd-master/1590/console may be
    caused by parser project

    Change-Id: I096b84d76e7aba1bea181e640eb2e3710a779d3c
    Signed-off-by: Julien <zhang.jun3g@zte.com.cn>

diff --git a/docs/submodules/parser b/docs/submodules/parser
index 445823e..6a24bbe 160000 (submodule)
--- a/docs/submodules/parser
+++ b/docs/submodules/parser
@@ -1 +1 @@
-Subproject commit 445823e739da83e7715f4f13e43e7b3fb62e7966
+Subproject commit 6a24bbe353242f78c2a2eb08f522cccea60befc4