Auto merge of #5059 - tobywhughes:master, r=alexcrichton

Clean with --verbose now prints path of what is being removed.

Added verbose output for the clean command. Simply takes whatever is passed into the rm_rf() function and outputs "Removing /whatever/the/path/to/remove/is"

[Issue this is being used for](https://github.com/rust-lang/cargo/issues/5056)