silenced default output of ovnkube-lib.sh and made it ENV dependning instead

Author: michaelalang

bindata/network/ovn-kubernetes/common/008-script-lib.yaml

@@ -10,7 +10,9 @@ metadata:
 data:
   ovnkube-lib.sh: |-
     #!/bin/bash
-    set -x
+    if [[ "${OVNKUBE_SH_VERBOSE:-}" == "true" ]]; then
+      set -x
+    fi
 {{- if .IsNetworkTypeLiveMigration }}
     if ip link show br-ex; then
       echo "br-ex exists"