frr:zebra: Crash in nexthops_free

Detailed Report: https://oss-fuzz.com/testcase?key=5391485297098752 Project: frr Fuzzing Engine: libFuzzer Fuzz Target: zebra Job Type: libfuzzerubsanfrr Platform Id: linux Crash Type: UNKNOWN READ Crash Address: 0x000000050002 Crash State: nexthopsfree ribunlink ribaddmultipathnhe Sanitizer:...