ovs: Bump submodule to latest OVS branch-3.4. #879

Job	Run time
Prepare container	3m 20s
osx clang --disable-ssl	1m 52s
linux rpm fedora	7m 23s
linux gcc --disable-ssl	2m 41s
linux clang --disable-ssl	2m 41s
linux gcc test -300	9m 11s
linux gcc test 301-600	6m 26s
linux gcc test 601- unstable	6m 31s
linux clang test sanitizers -300	12m 38s
linux clang test sanitizers 301-600	8m 42s
linux clang test sanitizers 601- unstable	10m 48s
linux gcc test -ljemalloc -300	10m 57s
linux gcc test -ljemalloc 301-600	6m 27s
linux gcc test -ljemalloc 601- unstable	6m 49s
linux gcc system-test-dpdk dpdk -100	17m 6s
linux gcc system-test-dpdk dpdk 101- unstable	14m 4s
linux gcc system-test-userspace -100	15m 46s
linux gcc system-test-userspace 101- unstable	13m 2s
linux gcc system-test -100	18m 22s
linux gcc system-test 101- unstable	16m 41s
linux clang system-test sanitizers -100	20m 16s
linux clang system-test sanitizers 101- unstable	18m 45s
linux x86 gcc --disable-ssl	2m 47s
	3h 53m 15s

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