Broken link for mktexlsr

[Sergio Callegari]

After todays update of texlive with `tlmgr update --all`, every update is 
failing with

tlmgr: mktexlsr failed (status -1), output:

and no output for mktexlsr.

This seems to be due to the fact that `... bin/x86_64-linux/mktexlsr` points to 
`../../texmf-dist/scripts/texlive/mktexlsr` with a broken symbolic link. The 
latter should be `../../texmf-dist/scripts/texlive/mktexlsr.pl`.

Fixing the link by hand seems to solve the issue.

Sergio