Cleanup manila/utils.py

The file has a lot of unsed code. The following code was removed:

variables:
 * ISO_TIME_FORMAT
 * PERFECT_TIME_FORMAT
 * DEFAULT_PASSWORD_SYMBOLS
 * EASIER_PASSWORD_SYMBOLS

functions:
 * find_config
 * fetchfile
 * create_channel
 * generate_uid
 * last_completed_audit_period
 * generate_password
 * generate_username
 * last_octet
 * get_my_linklocal
 * parse_mailmap
 * xhtml_escape
 * utf8
 * is_valid_boolstr
 * is_valid_ipv4
 * make_dev_path
 * sanitize_hostname
 * hash_file
 * temporary_mutation
 * generate_mac_address
 * strcmp_const_time
 * to_bytes

classes:
 * UndoManager

Change-Id: If49ca92b6665114de6782d056fa17985bd160426
Merge "Cleanup manila/utils.py"