Cleanup manila.utils module (part1)

Removed next functions:
- flatten_dict
- partition_dict
- map_dict_keys
- subset_dict
- check_isinstance
- convert_to_list_dict
- timefunc
- generate_glance_url
- logging_error
- remove_path_on_error
- str_dict_replace
- total_seconds

Usage of 'total_seconds' function was replaced with same
function from common code in timeutils.

Change-Id: I596441a919f9def81a6b60596e74af7a5de22427