s/get_vlan_id_from_tag/get_vlan_id_by_tag/

Change-Id: I0748e8317af3674e6f52652436d5393f93e8e8f4
diff --git a/db/db.py b/db/db.py
index 571ffa7..13eb039 100644
--- a/db/db.py
+++ b/db/db.py
@@ -111,7 +111,7 @@
         if vlan_id is not None:
             raise InputError("VLAN name %s is already in use" % name)
 
-        vlan_id = self.get_vlan_id_from_tag(tag)
+        vlan_id = self.get_vlan_id_by_tag(tag)
         if vlan_id is not None:
             raise InputError("VLAN tag %d is already in use" % int(tag))
 
@@ -273,7 +273,7 @@
     def get_vlan_id_by_name(self, name):
         return self._get_element("vlan_id", "vlan", "name", name)
 
-    def get_vlan_id_from_tag(self, tag):
+    def get_vlan_id_by_tag(self, tag):
         return self._get_element("vlan_id", "vlan", "tag", tag)
 
     def get_switch_name(self, switch_id):