nvmf: Fix timing issue in shutdown test

Change-Id: Ifaa33f85914e8b3abba424f1bfd3a6c03d7ca236
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/423750
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Chandler-Test-Pool: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

test/nvmf/common.sh

@@ -133,7 +133,20 @@ function get_ip_address()
 function nvmfcleanup()
 {
 	sync
-	rmmod nvme-rdma
+	set +e
+	for i in {1..20}; do
+		modprobe -v -r nvme-rdma nvme-fabrics
+		if [ $? -eq 0 ]; then
+			set -e
+			return
+		fi
+		sleep 1
+	done
+	set -e
+
+	# So far unable to remove the kernel modules. Try
+	# one more time and let it fail.
+	modprobe -v -r nvme-rdma nvme-fabrics
 }
 
 function nvmftestinit()