non_uppercase_statics should be renamed for constants

[mahkoh]

src/clang/ll.rs:794:1: 794:55 warning: static constant `CXIdxEntityRef_Implicit` should have an uppercase name such as `CXIDXENTITYREF_IMPLICIT`, #[warn(non_uppercase_statics)] on by default
src/clang/ll.rs:794 pub const CXIdxEntityRef_Implicit: ::libc::c_uint = 2;
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[alexcrichton]

cc @aturon, you may want to update rust-lang/rfcs#344 to rename this lint to something like non_uppercase_globals