2940 elfdump should return non-null on invalid file type

@@ -972,10 +972,11 @@
                 case ELF_K_ELF:
                         ret = decide(file, fd, elf, flags, wname, wfd, osabi);
                         break;
                 default:
                         (void) fprintf(stderr, MSG_INTL(MSG_ERR_BADFILE), file);
+                        ret = 1;
                         break;
                 }
 
                 (void) close(fd);
                 (void) elf_end(elf);