systemc: Fix a small bug in verify.py.

The src_dir method of the Test class was using the wrong attribute of
the test from the json file. It should use path, but was using src_dir.

Change-Id: Iaaaf31c31b11b68ecd7dd98807e6b78597cebb99
Reviewed-on: https://gem5-review.googlesource.com/12029
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/tests/verify.py

@@ -70,7 +70,7 @@ class Test(object):
         return os.path.join(self.build_dir, tests_rel_path, self.path)
 
     def src_dir(self):
-        return os.path.join(script_path, self.path)
+        return os.path.join(script_dir, self.path)
 
     def golden_dir(self):
         return os.path.join(self.src_dir(), 'golden')