systemvm: don't fork to curl to save password

[yadvr]

This fixes to avoid forking curl to save password but instead call
a HTTP POST url directly within Python code. This may reduce bottleneck
during high VM launches that require passwords.

Fixes #3182

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)

[yadvr]

@blueorangutan package

[blueorangutan]

@rhtyd a Jenkins job has been kicked to build packages. I'll keep you posted as I make progress.

[blueorangutan]

Packaging result: ✔centos6 ✔centos7 ✔debian. JID-55

[yadvr]

Can you review this @shwstppr @anuragaw

[anuragaw]

LGTM

[yadvr]

Tested by deploying macchnina with password script, feature works ok, no regressions seen.
@blueorangutan test

[blueorangutan]

@rhtyd a Trillian-Jenkins test job (centos7 mgmt + kvm-centos7) has been kicked to run smoke tests

[yadvr]

Env issue rekicking
@blueorangutan test

[blueorangutan]

@rhtyd a Trillian-Jenkins test job (centos7 mgmt + kvm-centos7) has been kicked to run smoke tests

[yadvr]

Re-kicked trillian job

[blueorangutan]

Trillian test result (tid-74)
Environment: kvm-centos7 (x2), Advanced Networking with Mgmt server 7
Total time taken: 28562 seconds
Marvin logs: https://github.com/blueorangutan/acs-prs/releases/download/trillian/pr3437-t74-kvm-centos7.zip
Smoke tests completed. 71 look OK, 0 have error(s)
Only failed tests results shown below:

Test	Result	Time (s)	Test File