[PATCH] Rename lld:*_error::_ -> lld:*_error::ErrorCode.

[Rui Ueyama]

  Renaming _ -> ErrorCode should follow the LLVM naming convention. Quote

  - Type names (including classes, structs, enums, typedefs, etc) should be nouns and start with an upper-case letter (e.g. TextFileReader).
  - Enum declarations (e.g. enum Foo {...}) are types, so they should follow the naming conventions for types. ...

http://llvm-reviews.chandlerc.com/D1851