[Minor] Rename method name

conf/statistic.conf

@@ -41,7 +41,7 @@ classifier "bayes" {
     symbol = "BAYES_SPAM";
     spam = true;
   }
-  learn_condition = "return require("lua_bayes_learn").autolearn"
+  learn_condition = "return require("lua_bayes_learn").can_learn"
 
   .include(try=true; priority=1) "$LOCAL_CONFDIR/local.d/classifier-bayes.conf"
   .include(try=true; priority=10) "$LOCAL_CONFDIR/override.d/classifier-bayes.conf"

lualib/lua_bayes_learn.lua

@@ -18,7 +18,7 @@ limitations under the License.
 
 local exports = {}
 
-exports.autolearn = function(task, is_spam, is_unlearn)
+exports.can_learn = function(task, is_spam, is_unlearn)
   local learn_type = task:get_request_header('Learn-Type')
 
   if not (learn_type and tostring(learn_type) == 'bulk') then