Trivial: Fix PVLAN_PLUGIN underscore

TrivialFix

Change-Id: I5986e8f1757067b470329d8b4cc9b4b9a84579a1
Signed-off-by: Elvira Garcia <egarciar@redhat.com>

Author: elvgarrui

neutron_lib/services/pvlan/constants.py

@@ -24,7 +24,7 @@
 
 PVLAN_TYPES = [ISOLATED_TYPE, PROMISCUOUS_TYPE, COMMUNITY_TYPE]
 
-PVLAN_PLUGIN = 'pvlan-plugin'
+PVLAN_PLUGIN = 'pvlan_plugin'
 
 COMMUNITY_NAME_REGEX = (
     "[a-zA-Z_.][a-zA-Z_.0-9]{0,%d}$" % (COMMUNITY_NAME_MAX_LEN - 1)