fix export model

tools/export_model.py

@@ -13,6 +13,11 @@
 # limitations under the License.
 
 import argparse
+import os
+import sys
+__dir__ = os.path.dirname(os.path.abspath(__file__))
+sys.path.append(__dir__)
+sys.path.append(os.path.abspath(os.path.join(__dir__, '..')))
 
 from ppcls.modeling import architectures
 from ppcls.utils.save_load import load_dygraph_pretrain