Check that file exists

src/freedombone-utils-onion

     onion_address=$(cat /var/lib/tor/hidden_service_${onion_service_name}/hostname)
 
     # Record the domain in the completion file
-    if ! grep "${onion_service_name} onion domain" $COMPLETION_FILE; then
-        echo "${onion_service_name} onion domain:${onion_address}" >> $COMPLETION_FILE
-    else
-        sed -i "s|${onion_service_name} onion domain.*|${onion_service_name} onion domain:${onion_address}|g" $COMPLETION_FILE
+    if [ -f $COMPLETION_FILE ]; then
+        if ! grep "${onion_service_name} onion domain" $COMPLETION_FILE; then
+            echo "${onion_service_name} onion domain:${onion_address}" >> $COMPLETION_FILE
+        else
+            sed -i "s|${onion_service_name} onion domain.*|${onion_service_name} onion domain:${onion_address}|g" $COMPLETION_FILE
+        fi
     fi
 
     echo $onion_address