Remove unnecessary dependencies.

Author: nnethercote

Cargo.lock

@@ -3716,7 +3716,6 @@ dependencies = [
  "rustc_const_eval",
  "rustc_data_structures",
  "rustc_error_codes",
- "rustc_error_messages",
  "rustc_errors",
  "rustc_expand",
  "rustc_feature",
@@ -3868,7 +3867,6 @@ dependencies = [
  "rustc_arena",
  "rustc_ast",
  "rustc_data_structures",
- "rustc_error_messages",
  "rustc_index",
  "rustc_macros",
  "rustc_serialize",

compiler/rustc_driver_impl/Cargo.toml

@@ -16,7 +16,6 @@ rustc_codegen_ssa = { path = "../rustc_codegen_ssa" }
 rustc_const_eval = { path = "../rustc_const_eval" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_error_codes = { path = "../rustc_error_codes" }
-rustc_error_messages = { path = "../rustc_error_messages" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_expand = { path = "../rustc_expand" }
 rustc_feature = { path = "../rustc_feature" }

compiler/rustc_hir/Cargo.toml

@@ -9,7 +9,6 @@ odht = { version = "0.3.1", features = ["nightly"] }
 rustc_arena = { path = "../rustc_arena" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_data_structures = { path = "../rustc_data_structures" }
-rustc_error_messages = { path = "../rustc_error_messages" }
 rustc_index = { path = "../rustc_index" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_serialize = { path = "../rustc_serialize" }