route-table: Avoid potential NULL ptr dereference. #6781

Job	Run time
build oss-fuzz fuzzers	3m 4s
osx clang --disable-ssl	1m 36s
libreswan (ubuntu-24.04)	4s
linux deb no dpdk	8m 33s
dpdk gcc (ubuntu-24.04)	6s
linux rpm fedora	4m 5s
clang-analyze-cache	11m 45s
linux gcc --disable-ssl	2m 36s
linux clang --disable-ssl	4m 43s
linux gcc c99	3m 55s
linux clang c99	3m 15s
linux gcc test	8m 29s
linux clang address,undefined test	17m 39s
linux gcc test --enable-shared	12m 35s
linux clang test --enable-shared	11m 27s
linux gcc check check-dpdk dpdk	20m 15s
linux clang check check-dpdk dpdk	20m 12s
linux gcc test -ljemalloc	9m 45s
linux clang test -ljemalloc	9m 13s
linux gcc --enable-afxdp	3m 3s
linux clang --enable-afxdp	3m 8s
linux gcc dpdk --enable-shared	4m 0s
linux clang dpdk --enable-shared	3m 59s
linux gcc dpdk-shared	2m 53s
linux clang dpdk-shared	3m 39s
linux gcc dpdk-shared --enable-shared	4m 58s
linux clang dpdk-shared --enable-shared	3m 51s
linux gcc m32 --disable-ssl	5m 44s
linux gcc check-ovsdb-cluster	6m 44s
linux gcc check-kernel -100	10m 26s
linux gcc check-kernel 100-	17m 36s
linux clang address,undefined check-kernel -100	13m 4s
linux clang address,undefined check-kernel 100-	20m 42s
linux gcc check-offloads -100	12m 32s
linux gcc check-offloads 100-	13m 9s
linux gcc dpdk check-system-userspace	15m 22s
linux clang address,undefined dpdk check-system-userspace	18m 20s
linux gcc dpdk check-system-tso	12m 37s
linux gcc dpdk check-afxdp	13m 50s
clang-analyze	10m 23s
	5h 53m 17s

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