Change a way for creating data dir in case of OVN.

Calculate the sudo usage with local variable.

Change-Id: I39dff770ff296dc06395acdb430a9cfe1722a30f

lib/neutron_plugins/ovn_agent

@@ -567,12 +567,13 @@ function init_ovn {
     # create new ones on each devstack run.
 
     _disable_libvirt_apparmor
+    local mkdir_cmd="mkdir -p ${OVN_DATADIR}"
 
-    if [[ "$OVN_BUILD_FROM_SOURCE" == "True" ]]; then
-        mkdir -p $OVN_DATADIR
-    else
-        sudo mkdir -p $OVN_DATADIR
+    if [[ "$OVN_BUILD_FROM_SOURCE" == "False" ]]; then
+        mkdir_cmd="sudo ${mkdir_cmd}"
     fi
+
+    $mkdir_cmd
     mkdir -p $OVS_DATADIR
 
     rm -f $OVS_DATADIR/*.db