Validate Python version. 3.5+ is required

subprocess.run() was added since Python 3.5+.

Author: jserv

scripts/gen-proc-version.py

@@ -1,9 +1,12 @@
 import subprocess
+import sys
 import string
 from datetime import datetime
 import argparse
 
 def run_cmd(cmd):
+    if sys.version_info < (3, 5):
+        return 'unknown'
     res = subprocess.run(cmd, universal_newlines=True,
                          stdout=subprocess.PIPE,
                          stderr=subprocess.STDOUT)