Revert "Bump remove_dir_all from 0.7.0 to 0.8.0"

This reverts commit cc7db67.

Author: Mark-Simulacrum

Cargo.lock

@@ -50,7 +50,7 @@ rust_team_data = { git = "https://github.com/rust-lang/team" }
 systemstat = "0.1.11"
 rustwide = { version = "0.15.0", features = ["unstable", "unstable-toolchain-ci"] }
 percent-encoding = "2.1.0"
-remove_dir_all = "0.8"
+remove_dir_all = "0.7"
 ctrlc = "3.1.3"
 prometheus = "0.7.0"
 cargo_metadata = "0.15"