git: CVE-2014-9938: does not sanitize branch names in $PS1 allowing command execution

[Salvatore Bonaccorso <carnil () debian org>]

Hi

MITRE has assigned CVE-2014-9938 for an older issue in the contrib
script in git, where git-prompt.sh did not sanitize branch name in
$PS1 exploitable for command execution by a malicious repository.

The upstream fix is

https://github.com/git/git/commit/8976500cbbb13270398d3b3e07a17b8cc7bff43f

Regards,
Salvatore