Fix bug with read_file_content. (#4628)
Fix bug with read_file_content. (#4628)

* Fix bug with read_file_content.

* Code review feedback.

yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli