Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - gitignore: Ignore non vsperf files

    .gitignore was updated to ignore following files:
    * VPP project directory
    * l2fwd binary files
    * tags

    JIRA: VSPERF-529

    Change-Id: Idc10eae7b14c72a863f3473e02cbdc7c47d31b41
    Signed-off-by: Cian Ferriter <cian.ferriter@intel.com>
    Reviewed-by: Martin Klozik <martinx.klozik@intel.com>
    Reviewed-by: Al Morton <acmorton@att.com>
    Reviewed-by: Christian Trautman <ctrautma@redhat.com>
    Reviewed-by: Sridhar Rao <sridhar.rao@spirent.com>
    Reviewed-by: Trevor Cooper <trevor.cooper@intel.com>

diff --git a/docs/submodules/vswitchperf b/docs/submodules/vswitchperf
index 7032b8e..af66b45 160000 (submodule)
--- a/docs/submodules/vswitchperf
+++ b/docs/submodules/vswitchperf
@@ -1 +1 @@
-Subproject commit 7032b8ec49833084b9e7c06442a9756a3ec7e501
+Subproject commit af66b453e1f361c39dc1b6999e07f54cc1fd63f6