Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Merge "Draft dovetail user guide first cut"
  - Draft dovetail user guide first cut

    Fixing comment issues and updating to new version of dovetail.

    Change-Id: Iaa9243d0a835f1d050fb925fa75b2a770168a8f4
    Signed-off-by: Wenjing Chu <chu.wenjing@gmail.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index f799fe4..f2a48df 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit f799fe4f81f46731147e7da255475d4bcc5261fd
+Subproject commit f2a48dfef3fab2ae37694728b144cc592837810b