ofproto-dpif: Fix removal of renamed datapath ports. #1763

Job	Run time
osx clang --disable-ssl	4m 29s
linux gcc --disable-ssl	3m 42s
linux clang --disable-ssl	3m 21s
linux gcc test 3.16	10m 9s
linux clang test 3.16 asan	18m 18s
linux gcc test --enable-shared	16m 21s
linux clang test --enable-shared	14m 23s
linux gcc test dpdk	21m 59s
linux clang test dpdk	28m 24s
linux gcc test -ljemalloc	10m 41s
linux clang test -ljemalloc	13m 30s
linux gcc 5.8 5.5 5.4 4.19	8m 10s
linux clang 5.8 5.5 5.4 4.19	9m 17s
linux gcc 4.14 4.9 4.4 3.16	8m 20s
linux clang 4.14 4.9 4.4 3.16	7m 49s
linux gcc afxdp 5.3	5m 38s
linux clang afxdp 5.3	4m 20s
linux gcc dpdk --enable-shared	16m 30s
linux clang dpdk --enable-shared	14m 21s
linux gcc dpdk-shared	14m 30s
linux clang dpdk-shared	17m 56s
linux gcc dpdk-shared --enable-shared	18m 36s
linux clang dpdk-shared --enable-shared	14m 44s
linux gcc m32 --disable-ssl	4m 30s
linux gcc deb	9m 12s
	4h 59m 10s

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