elf.rs: do not inline constant from goblin library
SELFMAG is declared [here](https://github.com/m4b/goblin/blob/de8aecc8f1e7f3de7d66a1511d3976cdf0335e0c/src/elf/header.rs#L91).
@@ -22,7 +22,7 @@ impl<'a> Elf<'a> {
if data.len() < header::SIZEOF_EHDR {
Err(format!("Elf: Not enough data: {} < {}", data.len(), header::SIZEOF_EHDR))
} else if &data[..header::SELFMAG] != header::ELFMAG {
- Err(format!("Elf: Invalid magic: {:?} != {:?}", &data[..4], header::ELFMAG))
+ Err(format!("Elf: Invalid magic: {:?} != {:?}", &data[..header::SELFMAG], header::ELFMAG))
} else if data.get(header::EI_CLASS) != Some(&header::ELFCLASS) {
Err(format!("Elf: Invalid architecture: {:?} != {:?}", data.get(header::EI_CLASS), header::ELFCLASS))
} else {
