* fix urpmi.update path #37432
* improve urpmi
* use get_bin_path rather than hard coding the path
* fix pep8 issue
* avoid using global
* - `RPM_PATH`, `URPMIUPDATE_PATH`, `URPME_PATH`) aren't constants, they should be lowercase rather than uppercase
- shorten too long lines
- remove unused import
* revert removed imports
* use lowercase rather than uppercase
* update doc
* update doc
* update doc after sanity check