Implement show_vlan

Change-Id: I5ae1211a4d944a93f91d95970156175862eb54f5
diff --git a/admin.py b/admin.py
index 64a869a..00971ea 100644
--- a/admin.py
+++ b/admin.py
@@ -49,6 +49,9 @@
 def dump_port(port):
     print port
 
+def dump_vlan(vlan):
+    print vlan
+
 #print '%s' % banner
 
 #print 'Connecting to DB...'
@@ -420,5 +423,14 @@
         print "Restored port_id %d back to base VLAN" % port_id
     except InputError as inst:
         print 'Failed: %s' % inst
+elif opts.show_vlan is not None:
+    try:
+        vlan = db.get_vlan_by_id(opts.show_vlan)
+        if vlan is not None:
+            dump_vlan(vlan)
+        else:
+            print 'No vlan found for vlan_id %d' % opts.show_vlan
+    except InputError as inst:
+        print 'Failed: %s' % inst
 else:
     print 'No recognised command given. Try -h for help'