controller: Watch for route changes. #4756

Job	Run time
osx clang --disable-ssl	1m 58s
Prepare container	3m 35s
linux rpm fedora	5m 34s
linux gcc --disable-ssl	3m 14s
linux clang --disable-ssl	2m 59s
linux gcc test -300	3m 8s
linux gcc test 301-600	3m 27s
linux gcc test 601- unstable	3m 22s
linux clang test sanitizers -300	4m 17s
linux clang test sanitizers 301-600	4m 24s
linux clang test sanitizers 601- unstable	5m 15s
linux gcc test -ljemalloc -300	3m 22s
linux gcc test -ljemalloc 301-600	3m 7s
linux gcc test -ljemalloc 601- unstable	3m 32s
linux gcc system-test-dpdk dpdk -100	3m 47s
linux gcc system-test-dpdk dpdk 101- unstable	3m 42s
linux gcc system-test-userspace -100	2m 54s
linux gcc system-test-userspace 101- unstable	2m 55s
linux gcc system-test -100	3m 10s
linux gcc system-test 101- unstable	3m 1s
linux clang system-test sanitizers -100	3m 46s
linux clang system-test sanitizers 101- unstable	4m 3s
linux x86 gcc --disable-ssl	3m 8s
	1h 21m 40s

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