Revert "Fix dependency on libsnmp-dev, must be >=5.7.2"

This reverts commit c62722ee304bfe54a3cb50851ee6eeb4a5327955.

libsnmp-dev >=5.7.2 depends on libc6 >= 2.17
Revert "Revert "Fix dependency on libsnmp-dev, must be >=5.7.2""

This reverts commit b8a10c08a00c404ae06b4897f6bc5b112e4190a2.
Make ipv6 routes in non default table appear in conf
Fix non default table ipv6 routes not being updated