fix variable reference in ledgers setup

Signed-off-by: Mic Bowman <mic.bowman@intel.com>

ledgers/ccf/setup.py

@@ -41,7 +41,7 @@
     pdo_version = subprocess.check_output('bin/get_version', cwd=root_dir).decode('ascii').strip()
 except Exception as e :
     warnings.warn('Failed to get pdo version, using the default')
-    pdo_contracts_version = '0.0.0'
+    pdo_version = '0.0.0'
 
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