merge: replace mutt_mktemp() with mutt_file_mkstemp()

 * pgp_class_application_handler()
 * pgp_class_decrypt_mime()
 * pgp_class_encrypted_handler()
 * pgp_class_encrypt_message()
 * pgp_class_traditional_encryptsign()
 * pgp_class_verify_one()
 * pgp_decrypt_part()
 * pgp_find_hash()
 * pgp_gpgme_decrypt_mime()
 * pgp_gpgme_encrypted_handler()
 * pgp_gpgme_extract_keys()
 * smime_class_build_smime_entity()
 * smime_class_decrypt_mime()
 * smime_class_invoke_import()
 * smime_class_verify_one()
 * smime_extract_certificate()
 * smime_extract_signer_certificate()
 * smime_gpgme_application_handler()
 * smime_gpgme_decrypt_mime()
 * smime_handle_cert_email()
 * smime_handle_entity()