fix an API change that caused a typeError

lib/commands/core.js

@@ -59,14 +59,18 @@ Core.getSession = function (Sessions, key) {
     return user;
 };
 
-Core.expireSession = function (Sessions, key, cb) {
+Core.expireSession = function (Sessions, safeKey) {
+    var session = Sessions[safeKey];
+    if (!session) { return; }
+    if (session.blobstage) {
+        session.blobstage.close();
+    }
+    delete Sessions[safeKey];
+};
+
+Core.expireSessionAsync = function (Env, safeKey, cb) {
     setTimeout(function () {
-        var session = Sessions[key];
+        Core.expireSession(Sessions, safeKey);
-        if (!session) { return; }
-        if (session.blobstage) {
-            session.blobstage.close();
-        }
-        delete Sessions[key];
         cb(void 0, 'OK');
     });
 };
@@ -77,10 +81,10 @@ var isTooOld = function (time, now) {
 
 Core.expireSessions = function (Sessions) {
     var now = +new Date();
-    Object.keys(Sessions).forEach(function (key) {
+    Object.keys(Sessions).forEach(function (safeKey) {
-        var session = Sessions[key];
+        var session = Sessions[safeKey];
         if (session && isTooOld(session.atime, now)) {
-            Core.expireSession(Sessions, key);
+            Core.expireSession(Sessions, safeKey);
         }
     });
 };

lib/rpc.js

@@ -130,7 +130,7 @@ const AUTHENTICATED_USER_SCOPED = {
     GET_TOTAL_SIZE: Pinning.getTotalSize,
     UPDATE_LIMITS: Quota.updateLimits,
     GET_LIMIT: Pinning.getLimit,
-    EXPIRE_SESSION: Core.expireSession,
+    EXPIRE_SESSION: Core.expireSessionAsync,
     REMOVE_PINS: Pinning.removePins,
     TRIM_PINS: Pinning.trimPins,
     SET_METADATA: Metadata.setMetadata,