Updated git submodules

Project: aai/aai-common master a6872c558e2e584422bc4dc24e233e6757c34281

AAI-1468 -1480 Add Conn /lan-port-config for CCVPN

Issue-ID: AAI-1480
Add lan-port-config schema element to network namespace
Add dhcp-service schema element
Add CCVPN EdgeRules for lan-port-config to service-instance and
dhcp-service
Update lan-port-config with ipv4-address and ipv6-address.
Update dhcp-service with server-ipv4-address and server-ipv6-address.

Accidentally squashed another two commits together:
Issue-ID: AAI-1468
Add connectivities sub-component to "network" namespace.
Add connectivities element, which is sequence of "connectivity".
Add connectivity element, which has numerous properties.
Add CCVPN EdgeRules for connectivity to service-instance and vpn-binding

Change-Id: I78f4cdc906e43750bb319ba4f3bdb6483ed7ea24
Signed-off-by: Keong Lim <keong.lim@huawei.com>

diff --git a/docs/submodules/aai/aai-common.git b/docs/submodules/aai/aai-common.git
index 922990e..a6872c5 160000 (submodule)
--- a/docs/submodules/aai/aai-common.git
+++ b/docs/submodules/aai/aai-common.git
@@ -1 +1 @@
-Subproject commit 922990e4abebf878de7eaf7ee3a7de48c22ced0d
+Subproject commit a6872c558e2e584422bc4dc24e233e6757c34281