objtool: Improve error message for bad file argument

If a nonexistent file is supplied to objtool, it complains with a
non-helpful error:

  open: No such file or directory

Improve it to:

  objtool: can't open file /.tmp_
  open: No such file or directory

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
1 file changed