fix session API broken and SQL pretection

conf/app.ini

@@ -163,10 +163,6 @@ ENABLE_SET_COOKIE = true
 GC_INTERVAL_TIME = 86400
 ; Session life time, default is 86400
 SESSION_LIFE_TIME = 86400
-; session id hash func, Either "sha1", "sha256" or "md5" default is sha1
-SESSION_ID_HASHFUNC = sha1
-; Session hash key, default is use random string
-SESSION_ID_HASHKEY =
 
 [picture]
 ; The place to picture data, either "server" or "qiniu", default is "server"