clean_unused_caches: Allow the main function to accept `Namespace` args.
clean_unused_caches: Allow the main function to accept `Namespace` args.

This commit will allow us to pass the arguments in the
'clean...' functions when calling the `main` function (in
`provision`). It also changes args parsing
function location to `if __name__ == "__main__"` block as
we wouldn't need it to parse args when we call the
function.

rht/zulip,punchagan/zulip,eeshangarg/zulip,eeshangarg/zulip,rht/zulip,kou/zulip,hackerkid/zulip,kou/zulip,rht/zulip,eeshangarg/zulip,punchagan/zulip,kou/zulip,zulip/zulip,eeshangarg/zulip,punchagan/zulip,kou/zulip,rht/zulip,andersk/zulip,punchagan/zulip,rht/zulip,punchagan/zulip,kou/zulip,eeshangarg/zulip,andersk/zulip,hackerkid/zulip,kou/zulip,zulip/zulip,rht/zulip,punchagan/zulip,zulip/zulip,eeshangarg/zulip,punchagan/zulip,hackerkid/zulip,kou/zulip,zulip/zulip,andersk/zulip,hackerkid/zulip,eeshangarg/zulip,andersk/zulip,andersk/zulip,zulip/zulip,andersk/zulip,andersk/zulip,zulip/zulip,rht/zulip,hackerkid/zulip,zulip/zulip,hackerkid/zulip,hackerkid/zulip