vhost: fix coverity warning
vhost: fix coverity warning

Change-Id: Ifb9f8d2528142ad9f11a2b6d5ac10ff9639dd5d6
Signed-off-by: Pierre Pfister <e31bfcc197987a594da168a19bf32d37137e11a7@cisco.com>

milanlenco/vpp,vpp-dev/vpp,vpp-dev/vpp,milanlenco/vpp,chrisy/vpp,FDio/vpp,vpp-dev/vpp,chrisy/vpp,GabrielGanne/vpp-flowtable,milanlenco/vpp,GabrielGanne/vpp-flowtable,chrisy/vpp,milanlenco/vpp,milanlenco/vpp,chrisy/vpp,chrisy/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,GabrielGanne/vpp-flowtable,FDio/vpp,FDio/vpp,GabrielGanne/vpp-flowtable,chrisy/vpp,GabrielGanne/vpp-flowtable,FDio/vpp,chrisy/vpp,milanlenco/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,GabrielGanne/vpp-flowtable,vpp-dev/vpp