Handle -NLE_AGAIN in nl_cache_mngr_data_ready
Handle -NLE_AGAIN in nl_cache_mngr_data_ready

Since commit "nl: Return -NLE_AGAIN if non-blocking socket would block",
nl_cache_mngr_data_ready returns -NLE_AGAIN to callers on non-blocking sockets.
Change it to consider -NLE_AGAIN as a non-error case as it is expected behavior
with the nl_recv changes.

Signed-off-by: Thomas Graf <17c2d8920621522552b392f72d8fdb4d1e866b44@suug.ch>

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