fixed partially problem with web2py_filesystem on GAE

VERSION

@@ -1 +1 @@
-Version 2.9.6-stable+timestamp.2014.09.03.10.52.25
+Version 2.9.6-stable+timestamp.2014.09.03.16.28.59

gluon/dal.py

@@ -4592,19 +4592,23 @@ class DatabaseStoredFile:
     def escape(self, obj):
         return self.db._adapter.escape(obj)
 
+    @classmethod
+    def try_create_web2py_filesystem(db):
+        if not DatabaseStoredFile.web2py_filesystem:
+            if db._adapter.dbengine == 'mysql':
+                sql = "CREATE TABLE IF NOT EXISTS web2py_filesystem (path VARCHAR(255), content LONGTEXT, PRIMARY KEY(path) ) ENGINE=InnoDB;"
+            elif db._adapter.dbengine in ('postgres', 'sqlite'):
+                sql = "CREATE TABLE IF NOT EXISTS web2py_filesystem (path VARCHAR(255), content TEXT, PRIMARY KEY(path));"
+            db.executesql(sql)
+            DatabaseStoredFile.web2py_filesystem = True
+ 
     def __init__(self, db, filename, mode):
         if not db._adapter.dbengine in ('mysql', 'postgres', 'sqlite'):
             raise RuntimeError("only MySQL/Postgres/SQLite can store metadata .table files in database for now")
         self.db = db
         self.filename = filename
         self.mode = mode
-        if not self.web2py_filesystem:
-            if db._adapter.dbengine == 'mysql':
-                sql = "CREATE TABLE IF NOT EXISTS web2py_filesystem (path VARCHAR(255), content LONGTEXT, PRIMARY KEY(path) ) ENGINE=InnoDB;"
-            elif db._adapter.dbengine in ('postgres', 'sqlite'):
-                sql = "CREATE TABLE IF NOT EXISTS web2py_filesystem (path VARCHAR(255), content TEXT, PRIMARY KEY(path));"
-            self.db.executesql(sql)
-            DatabaseStoredFile.web2py_filesystem = True
+        DatabaseStoredFile.try_create_web2py_filesystem(db)
         self.p = 0
         self.data = ''
         if mode in ('r', 'rw', 'a'):
@@ -4655,6 +4659,9 @@ class DatabaseStoredFile:
     def exists(db, filename):
         if exists(filename):
             return True
+
+        DatabaseStoredFile.try_create_web2py_filesystem(db)
+
         query = "SELECT path FROM web2py_filesystem WHERE path='%s'" % filename
         try:
             if db.executesql(query):