mac-cache: Fix expiration of active FDB entry due to skipped update. #2599

Job	Run time
Prepare container	2m 20s
dpdk gcc	7s
linux rpm fedora	7m 26s
osx clang --disable-ssl	2m 0s
linux gcc --disable-ssl	2m 14s
linux clang --disable-ssl	2m 18s
linux gcc test -300	9m 9s
linux gcc test 301-600	6m 25s
linux gcc test 601- unstable	6m 1s
linux clang test sanitizers -300	11m 45s
linux clang test sanitizers 301-600	8m 53s
linux clang test sanitizers 601- unstable	9m 56s
linux gcc test -ljemalloc -300	9m 44s
linux gcc test -ljemalloc 301-600	6m 29s
linux gcc test -ljemalloc 601- unstable	6m 25s
linux gcc system-test-dpdk dpdk -100	15m 58s
linux gcc system-test-dpdk dpdk 101- unstable	11m 39s
linux gcc system-test-userspace -100	15m 1s
linux gcc system-test-userspace 101- unstable	10m 48s
linux gcc system-test -100	17m 46s
linux gcc system-test 101- unstable	14m 32s
linux clang system-test sanitizers -100	19m 31s
linux clang system-test sanitizers 101- unstable	16m 11s
linux x86 gcc --disable-ssl	2m 25s
	3h 35m 3s

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