bug#21319: `package-install-file' fails with CRLF (Windows) line endings

[steckerhalter <emacs@postmomentum.ch>]

package.el contains this code:

(defun package-install-file (file)
  "Install a package from a file.
The file can either be a tar file or an Emacs Lisp file."
  (interactive "fPackage file name: ")
  (with-temp-buffer
    (insert-file-contents-literally file)
    (when (string-match "\\.tar\\'" file) (tar-mode))
    (package-install-from-buffer)))

Since `insert-file-contents-literally' does not do any conversion
`package-buffer-info' fails to parse the info if the file is .el and
contains CRLF line endings. It then errors out with:

Debugger entered--Lisp error: (error "Package lacks a \"Version\" or
\"Package-Version\" header")
  signal(error ("Package lacks a \"Version\" or \"Package-Version\" header"))
  error("Package lacks a \"Version\" or \"Package-Version\" header")
  package-buffer-info()

This affects all recent Emacs versions (including trunk).

What we did now is to replace `insert-file-contents-literally' with
`insert-file-contents' dynamically for non-tar files and that seems to
work, although I'm not sure if that's a good solution since I don't
know if there might be side-effects somewhere that can cause other
problems.

The other solution I can think of might be to adapt the regexp in
`package-buffer-info` so that in can deal with CRLF.

cheers,
steckerhalter