swab(1): fixes not using strerror(3)

src/swab.rs

@@ -29,8 +29,11 @@ use getopt::GetOpt;
 extern crate sysexits;
 use sysexits::{ EX_OK, EX_OSERR, EX_USAGE };
 
+extern crate strerror;
+use strerror::StrError;
+
 fn oserr(s: &str, e: Error) -> ExitCode {
-	eprintln!("{}: {}", s, e);
+	eprintln!("{}: {}", s, e.strerror());
 	ExitCode::from(EX_OSERR as u8)
 }