Fix typos in common.go and swagger.yml

[yugyeong2]

This PR addresses two typo corrections found in the common.go and swagger.yml files.

1. common.go: common.go: Fixed a typo in the comment for LbSelRrPersist.

   • The word "connectons" was corrected to "connections" in the comment:

2. swagger.yml: swagger.yml: Corrected a typo in the word "Maintanence".

   • The word "Maintanence" was replaced with "Maintenance" in all occurrences within the swagger.yml file.

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