Extract gpg ids fails when locale is not en-XX

[alexanderBendo]

extract_fingerprints_from_cmd extracts keys by matching the string Key fingerprint but commands such as apt-key finger or gpg --with-fingerprint will output a different string if LANG is not set to english. For example, in a system configured with LANG=es_ES the actual string is Huella de clave, and so the function always returns an empty list, which causes new keys not being installed.