Auto merge of #4623 - alexcrichton:remove-lock, r=matklad

Delete Cargo.lock from this repo

There's now a lock file upstream in rust-lang/rust so the one here isn't
actually used, and otherwise this crate is used as a dependency so the lock file
isn't respected anyway!

Author: bors

.gitignore

@@ -1,12 +1,12 @@
 /target
+Cargo.lock
 .cargo
 /config.stamp
 /Makefile
 /config.mk
 src/doc/build
 src/etc/*.pyc
 src/registry/target
-src/registry/Cargo.lock
 rustc
 __pycache__
 .idea/