Bug 15163370 - Part 1: Dedupe sha2 and related dependencies. r=froydnj

This also removes the lalrpop files from the .git/hgignore as that
breaks the build since lalrpop now includes lrgrammar in the published
crate and that file needs to be vendored

--HG--
extra : histedit_source : 38900d8994d9661b2e710eca708981ca458365fb

.gitignore

@@ -157,5 +157,3 @@ lextab.py
 !.vscode/extensions.json
 !.vscode/tasks.json
 
-# Ignore file generated by lalrpop at build time.
-third_party/rust/lalrpop/src/parser/lrgrammar.rs

.hgignore

@@ -188,8 +188,5 @@ tps_result\.json
 ^testing/raptor/raptor/tests/.*.json
 ^testing/raptor/webext/raptor/auto_gen_test_config.js
 
-# Ignore file generated by lalrpop at build time.
-^third_party/rust/lalrpop/src/parser/lrgrammar.rs
-
 # Ignore the build directories of WebRender standalone builds.
 gfx/wr/target/