northd: Use the same UUID for SB representation of Load_Balancer. #3274

Job	Run time
osx clang --disable-ssl	1m 50s
Prepare container	1m 2s
linux rpm fedora	6m 47s
linux gcc --disable-ssl	2m 36s
linux clang --disable-ssl	2m 35s
linux gcc test -300	9m 6s
linux gcc test 301-600	6m 17s
linux gcc test 601- unstable	6m 34s
linux clang test sanitizers -300	12m 51s
linux clang test sanitizers 301-600	9m 3s
linux clang test sanitizers 601- unstable	11m 34s
linux gcc test -ljemalloc -300	9m 43s
linux gcc test -ljemalloc 301-600	6m 26s
linux gcc test -ljemalloc 601- unstable	6m 59s
linux gcc system-test-dpdk dpdk -100	16m 53s
linux gcc system-test-dpdk dpdk 101- unstable	14m 35s
linux gcc system-test-userspace -100	16m 0s
linux gcc system-test-userspace 101- unstable	13m 15s
linux gcc system-test -100	18m 35s
linux gcc system-test 101- unstable	17m 23s
linux clang system-test sanitizers -100	20m 30s
linux clang system-test sanitizers 101- unstable	19m 25s
linux x86 gcc --disable-ssl	2m 34s
	3h 52m 33s

Provide feedback