fix reproducible build summary giving invalid branch and commit id

fix #378
also fix unrelated error in nightly rustdoc CI

crates/arti-testing/src/main.rs

@@ -2,7 +2,7 @@
 //!
 //! Example use:
 //!
-//! ```ignore
+//! ```sh
 //! $ cat ~/.arti_testing.toml
 //! [storage]
 //!

maint/reproducible_build

@@ -93,6 +93,7 @@ EOF
 		UNATTENDED=yes OSX_VERSION_MIN=10.7 ./build.sh
 		# copy it to gitlab build-dir so it may get cached
 		cp -r /arti/osxcross "$here"
+		cd ..
 	fi
 
 	PATH="/arti/osxcross/target/bin:$PATH" \