Add missing configuration key LoginDatabase.SynchThreads.

(cherry picked from commit b23a6aeaff403266491ea75207558bf9917b9cc4)

# Conflicts:
#	src/server/bnetserver/bnetserver.conf.dist

src/server/authserver/authserver.conf.dist

@@ -183,6 +183,13 @@ LoginDatabaseInfo = "127.0.0.1;3306;trinity;trinity;auth"
 
 LoginDatabase.WorkerThreads = 1
 
+#
+#    LoginDatabase.SynchThreads
+#        Description: The amount of MySQL connections spawned to handle.
+#        Default:     1 - (LoginDatabase.WorkerThreads)
+
+LoginDatabase.SynchThreads  = 1
+
 #
 ###################################################################################################