build.rs: remove unused ::self import Fixes Rust compiler warning: warning: the item `chromeos_dbus_bindings` is imported redundantly --> /[...]/chromiumos/src/third_party/tlsdate/build.rs:9:30 BUG=None TEST=cargo +nightly build Change-Id: Ia304e9d97fe5ecd132c90100989fc7759f6c8937 Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/tlsdate/+/5513104 Reviewed-by: Jorge Lucangeli Obes <[email protected]> Tested-by: Daniel Verkamp <[email protected]> Commit-Queue: Daniel Verkamp <[email protected]>