ofproto-dpif: Fix removal of renamed datapath ports. #2190

Job	Run time
osx clang --disable-ssl	3m 51s
linux gcc --disable-ssl	3m 58s
linux clang --disable-ssl	3m 32s
linux gcc test 3.16	10m 25s
linux clang test 3.16 asan	22m 18s
linux gcc test --enable-shared	18m 0s
linux clang test --enable-shared	17m 8s
linux gcc test dpdk	23m 23s
linux clang test dpdk	21m 31s
linux gcc test -ljemalloc	12m 6s
linux clang test -ljemalloc	13m 7s
linux gcc 5.8 5.5 5.4 4.19	10m 45s
linux clang 5.8 5.5 5.4 4.19	7m 49s
linux gcc 4.14 4.9 4.4 3.16	7m 4s
linux clang 4.14 4.9 4.4 3.16	8m 7s
linux gcc afxdp 5.3	4m 11s
linux clang afxdp 5.3	5m 49s
linux gcc dpdk --enable-shared	19m 27s
linux clang dpdk --enable-shared	15m 3s
linux gcc dpdk-shared	15m 51s
linux clang dpdk-shared	15m 26s
linux gcc dpdk-shared --enable-shared	20m 14s
linux clang dpdk-shared --enable-shared	20m 26s
linux gcc m32 --disable-ssl	3m 58s
linux gcc deb	9m 12s
	5h 12m 41s

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