[SAI-PTF]add conditional import for unit test (opencomputeproject#1656)

* [SAI-PTF]add conditional import for unit test

Signed-off-by: richardyu-ms <richard.yu@microsoft.com>

* [SAI-PTF]add conditional import for unit test

Signed-off-by: richardyu-ms <richard.yu@microsoft.com>

Signed-off-by: richardyu-ms <richard.yu@microsoft.com>

ptf/utest/TemplateTest.py

@@ -1,5 +1,10 @@
 from BasicTest import BasicMockedTest
-from meta.sai_adapter import *
+# Try to import from local build folder
+# If cannot import then try to import from global folder
+try:
+    from meta.sai_adapter import *
+except ImportError:
+    from sai_thrift.sai_adapter import *
 from MockClient import MockSuccessClient
 import unittest
 
@@ -47,7 +52,3 @@ def check_file_contains(self, file, content):
                 if content in line:
                     return True
         return False
-
-
-if __name__ == '__main__':
-    unittest.main()