Problem using --doc option on install

[Nick Payne]

Using the --doc option on Lilypond install fails to download the doc 
tarball if a path is specified to the install file. i.e. On my system, 
if I run the install from the folder containing the file, the download 
of the doc tarball succeeds:

address@hidden ~/Downloads/lilypond $ sudo sh 
lilypond-2.18.0-1.linux-64.sh --doc

lilypond installer for version 2.18.0 release 1,
x86_64 build.
For a list of options, abort (^C) then do:
sh lilypond-2.18.0-1.linux-64.sh --help


You are about to install LilyPond in /usr/local/lilypond
A script in /usr/local/bin will be created as a shortcut.

Press ^C to abort, or Enter to proceed.

Making /usr/local/lilypond
Creating script /usr/local/bin/lilypond
Creating script /usr/local/bin/lilypond-wrapper.python
Creating script /usr/local/bin/lilypond-wrapper.guile
Creating script /usr/local/bin/uninstall-lilypond
Untarring lilypond-2.18.0-1.linux-64.sh
No ./lilypond-2.18.0-1.documentation.tar.bz2 found, downloading.
--2014-01-01 06:53:04-- 
http://lilypond.org/download/binaries/documentation/lilypond-2.18.0-1.documentation.tar.bz2
Resolving lilypond.org (lilypond.org)... 82.94.241.173
Connecting to lilypond.org (lilypond.org)|82.94.241.173|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 234535213 (224M) [application/x-tar]
Saving to: 'lilypond-2.18.0-1.documentation.tar.bz2’

0% [ ] 971,264 323KB/s


However, run the install from elsewhere with the path to the install sh 
specified, and the download of the doc tarball fails:

address@hidden ~ $ sudo sh 
~/Downloads/lilypond/lilypond-2.18.0-1.linux-64.sh --doc

lilypond installer for version 2.18.0 release 1,
x86_64 build.
For a list of options, abort (^C) then do:
sh /home/nick/Downloads/lilypond/lilypond-2.18.0-1.linux-64.sh --help


You are about to install LilyPond in /usr/local/lilypond
A script in /usr/local/bin will be created as a shortcut.

Press ^C to abort, or Enter to proceed.

Making /usr/local/lilypond
Creating script /usr/local/bin/lilypond
Creating script /usr/local/bin/lilypond-wrapper.python
Creating script /usr/local/bin/lilypond-wrapper.guile
Creating script /usr/local/bin/uninstall-lilypond
Untarring /home/nick/Downloads/lilypond/lilypond-2.18.0-1.linux-64.sh
No 
.//home/nick/Downloads/lilypond/lilypond-2.18.0-1.documentation.tar.bz2 
found, downloading.
--2013-12-31 21:33:33-- 
http://lilypond.org/download/binaries/documentation//home/nick/Downloads/lilypond/lilypond-2.18.0-1.documentation.tar.bz2
Resolving lilypond.org (lilypond.org)... 82.94.241.173
Connecting to lilypond.org (lilypond.org)|82.94.241.173|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2013-12-31 21:33:35 ERROR 404: Not Found.