check_names: Use the same Python executable instead of python3

Fix build failure in environments where `python3` doesn't exist or is too
old.

Signed-off-by: Gilles Peskine <[email protected]>

scripts/check_names.py

@@ -850,7 +850,7 @@ class TFPSACryptoCodeParser(CodeParser):
             # Use check=True in all subprocess calls so that failures are raised
             # as exceptions and logged.
             subprocess.run(
-                ["python3", "scripts/config.py", "full"],
+                [sys.executable, "scripts/config.py", "full"],
                 universal_newlines=True,
                 check=True
             )
@@ -1019,7 +1019,7 @@ class MBEDTLSCodeParser(CodeParser):
             # Use check=True in all subprocess calls so that failures are raised
             # as exceptions and logged.
             subprocess.run(
-                ["python3", "scripts/config.py", "full"],
+                [sys.executable, "scripts/config.py", "full"],
                 universal_newlines=True,
                 check=True
             )