Improvement to random port allocation for redis testing

[sameh-farouk]

Description

While running the Redis test suite it tries to find a random port for redis-server using the python random module. using this method it is possible to get an already used port and the test will then fail.

to get a free port properly we should bind to port 0 to make the OS pick a random available port from 1024 to 65535.

Changes

• switch to use the nettools's get_free_port function.

Checklist

• Pre-commit hook is installed to do formatting checks before committing code...etc
• Tests included
• Build pass
• Documentation
• Code format and docstrings

[codecov-commenter]

Codecov Report

Merging #591 (2fa81dc) into development (2eec7af) will increase coverage by 0.14%.
The diff coverage is n/a.

@@               Coverage Diff               @@
##           development     #591      +/-   ##
===============================================
+ Coverage        69.67%   69.81%   +0.14%     
===============================================
  Files               84       84              
  Lines             4283     4283              
===============================================
+ Hits              2984     2990       +6     
+ Misses            1299     1293       -6     

Impacted Files	Coverage Δ
jumpscale/sals/process/__init__.py	65.28% <0.00%> (+1.10%)	⬆️
jumpscale/tools/startupcmd/startupcmd.py	86.79% <0.00%> (+1.25%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 2eec7af...2fa81dc. Read the comment docs.

[abom]

@sameh-farouk I think this need to be used elsewhere too in tests, can we check other tests?

[sameh-farouk]

@abom updated to include those tests from process sal