doc: Correct OpenFlow tables numbers. #4796

Job	Run time
linux rpm fedora	6m 53s
osx clang --disable-ssl	2m 0s
Prepare container	3m 36s
linux gcc --disable-ssl	2m 36s
linux clang --disable-ssl	2m 47s
linux gcc test -300	9m 38s
linux gcc test 301-600	6m 38s
linux gcc test 601- unstable	7m 10s
linux clang test sanitizers -300	13m 6s
linux clang test sanitizers 301-600	9m 28s
linux clang test sanitizers 601- unstable	12m 54s
linux gcc test -ljemalloc -300	10m 15s
linux gcc test -ljemalloc 301-600	6m 52s
linux gcc test -ljemalloc 601- unstable	7m 21s
linux gcc system-test-dpdk dpdk -100	16m 48s
linux gcc system-test-dpdk dpdk 101- unstable	15m 6s
linux gcc system-test-userspace -100	15m 55s
linux gcc system-test-userspace 101- unstable	13m 58s
linux gcc system-test -100	18m 23s
linux gcc system-test 101- unstable	17m 58s
linux clang system-test sanitizers -100	20m 28s
linux clang system-test sanitizers 101- unstable	20m 5s
linux x86 gcc --disable-ssl	2m 33s
	4h 2m 28s

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