Fix nfs route bug

[iishitahere]

Description

This PR fixes the issue #10163, where the secondary storage VM fails to add a static route to the NFS server, causing a No route to host error. The _storageIp was previously null, resulting in failed route addition (via null).

Changes Made

• Improved _storageIp handling to prevent null values.
• Added utility methods to validate NFS server reachability.
• Enhanced error handling and logging.

Testing

• Verified successful template uploads to secondary storage.
• Checked route addition on the SSVM.
• Ran unit tests (S3TemplateTest, etc.), all tests passed successfully.

[weizhouapache]

thanks @iishitahere for the PR

I would suggest you keep this PR clean and remove all unnecessary changes
IMHO, this PR could be around 5 lines of code changes

[iishitahere]

thanks @iishitahere for the PR

I would suggest you keep this PR clean and remove all unnecessary changes IMHO, this PR could be around 5 lines of code changes

Thank you for your feedback and for reviewing the PR. I sincerely appreciate your guidance.

I apologize for the unnecessary changes. I would like to keep the PR as clean and concise as possible. Could you kindly point out where exactly the code changes are needed so that I can work on it and ensure the PR is focused on resolving the issue effectively?

Thank you for your time and support. I look forward to your response.

Best regards,
Ishita Jaiswal