DeprecationWarning in update-verification-metadata.py

[raphiz]

There is a DeprecationWarning from Python in the output when running the update-verification-metadata utility script:

/nix/store/j4jkfi2a9as7hh6z7x4r5jfl8r9xz8i0-update-verification-metadata.py:15: DeprecationWarning: Testing an element's truth value will always return True in future versions.  Use specific 'len(elem)' or 'elem is not None' test instead.
  if (components):

Should be an easy fix