ipam: Do not report error for static assigned IPs. #3211

Job	Run time
osx clang --disable-ssl	2m 25s
dpdk gcc	9s
linux rpm fedora	6m 56s
Prepare container	2m 32s
linux gcc --disable-ssl	2m 17s
linux clang --disable-ssl	2m 20s
linux gcc test -300	8m 58s
linux gcc test 301-600	5m 40s
linux gcc test 601- unstable	6m 17s
linux clang test sanitizers -300	11m 53s
linux clang test sanitizers 301-600	8m 4s
linux clang test sanitizers 601- unstable	9m 35s
linux gcc test -ljemalloc -300	9m 12s
linux gcc test -ljemalloc 301-600	5m 44s
linux gcc test -ljemalloc 601- unstable	6m 3s
linux gcc system-test-dpdk dpdk -100	16m 10s
linux gcc system-test-dpdk dpdk 101- unstable	11m 16s
linux gcc system-test-userspace -100	15m 0s
linux gcc system-test-userspace 101- unstable	11m 27s
linux gcc system-test -100	17m 29s
linux gcc system-test 101- unstable	13m 41s
linux clang system-test sanitizers -100	19m 24s
linux clang system-test sanitizers 101- unstable	15m 9s
linux x86 gcc --disable-ssl	2m 16s
	3h 29m 57s

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