VPP-574: fix VPP hang during security group configuration on a suspended VM
VPP-574: fix VPP hang during security group configuration on a suspended VM

The unix connect() in vhost-user driver in VPP is blocking, and
a non-expedient accept() on the other side causes the entire VPP to hang.

Solution: set the nonblocking flag for the socket fd before calling
connect(), and set the socket back to blocking after the accept() succeeds.

Change-Id: Ia5ee782037eeffabdad71db8241f476a048a4f6f
Signed-off-by: Andrew Yourtchenko <eb6233fe2fbd585844f4fb8426b53b186ab379b1@gmail.com>

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