Fix for kubelet startup script when using azure cni

[madhanrm]

What this PR does / why we need it:
For 1803 & below, to workaround a known issue, we need the network to be recreated on reboot. This PR adds that workaround into the Kubeletstartup script.

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:
As soon as the fix for the original issue is serviced (probably in June Servicing), we can remove this for 1803. But may still need it for 1709.

If applicable:

• documentation
• unit tests
• tested backward compatibility (ie. deploy with previous version, upgrade with this branch)

Release note:

[saiyan86]

@madhanrm Hi Madhan, could you please add some descriptions to this PR? Thanks!

[codecov]

Codecov Report

Merging #3301 into master will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3301      +/-   ##
==========================================
- Coverage    52.9%   52.87%   -0.04%     
==========================================
  Files         104      104              
  Lines       15716    15714       -2     
==========================================
- Hits         8315     8308       -7     
- Misses       6668     6671       +3     
- Partials      733      735       +2

[madhanrm]

@saiyan86 Have updated the description.

[madhanrm]

@saiyan86 can you get this PR approved.

[saiyan86]

/assign @jackfrancis

[saiyan86]

/lgtm

[acs-bot]

@saiyan86: changing LGTM is restricted to assignees, and assigning you to the PR failed.

In response to this:

/lgtm

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[saiyan86]

@madhanrm Thanks for updating. I just approved the PR.

[jackfrancis]

/lgtm pending E2E

[acs-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jackfrancis, madhanrm, saiyan86

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