api: retry sending fd on EAGAIN
api: retry sending fd on EAGAIN

Type: improvement

Signed-off-by: Florin Coras <c9715e5cdf0718c2e9b10678757dfb027875eba2@cisco.com>
Change-Id: I04117636ad95b706e3dd9331f00bd80e57d26d7f

FDio/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,FDio/vpp,FDio/vpp,chrisy/vpp