Bug 8248: Don't access DSBE from different threads
With Epoll we may have more than one LispSouthboundHandler thread, and
they may access the same DataStoreBackEnd (DSBE) instance concurrently.
This patch moves DSBE access to the single threaded
LispSouthboundPlugin. Additionally, it implements some suggestions from
the following thread:
https://lists.opendaylight.org/pipermail/release/2017-April/010273.html
Change-Id: I32f48b6dcb58b241a4a679f7145bd36b5f410861
Signed-off-by: Lorand Jakab <lojakab@cisco.com>