cache_mngr: Make providing the result pointer to nl_cache_mngr_add() optional
cache_mngr: Make providing the result pointer to nl_cache_mngr_add() optional

tgraf/libnl,teto/libnl_old,honsys/libnl,cfriedt/libnl,claudelee/libnl,congwang/libnl,tklauser/libnl,tgraf/libnl,baloo/libnl,vyos/libnl3,vyos/libnl3,Distrotech/libnl,cfriedt/libnl,kolyshkin/libnl,Distrotech/libnl,greearb/libnl-ct,tklauser/libnl,congwang/libnl,thom311/libnl,socketpair/libnl,Distrotech/libnl,claudelee/libnl,karlhiramoto/libnl,honsys/libnl,cfriedt/libnl,HolyShitMan/libnl-1,houstar/libnl,UnicronNL/libnl3,chitranshi/libnl,teto/libnl_old,congwang/libnl,karlhiramoto/libnl,UnicronNL/libnl3,vyos/libnl3,dsahern/libnl,HolyShitMan/libnl-1,mshirley/libnl,baloo/libnl,HolyShitMan/libnl-1,kolyshkin/libnl,UnicronNL/libnl3,houstar/libnl,honsys/libnl,honsys/libnl,thom311/libnl,cyclops8456/libnl3,socketpair/libnl,kolyshkin/libnl,tgraf/libnl,UnicronNL/libnl3,houstar/libnl,dsahern/libnl,vyos/libnl3,tklauser/libnl,socketpair/libnl,claudelee/libnl,HolyShitMan/libnl-1,karlhiramoto/libnl,tklauser/libnl,dsahern/libnl,baloo/libnl,cyclops8456/libnl3,kolyshkin/libnl,tgraf/libnl,thom311/libnl,cyclops8456/libnl3,Distrotech/libnl,mshirley/libnl,houstar/libnl,dsahern/libnl,greearb/libnl-ct,cfriedt/libnl,teto/libnl_old,chitranshi/libnl,teto/libnl_old,mshirley/libnl,karlhiramoto/libnl,chitranshi/libnl,mshirley/libnl,chitranshi/libnl,congwang/libnl,cyclops8456/libnl3,greearb/libnl-ct,baloo/libnl,claudelee/libnl