bug#25966: Fix bug 25957 and updates gitolite

[ng0]

These two patches:

* update gitolite to 3.6.6,
* (attempt to) fix #25957.

I write attempt, in theory this closes the bug. I don't run this on my
server. I have greped for more occurences of /usr/bin/perl, and the ones
I had problems with are gone, remaining are 2 which are completely
unrelated to the bug and to the issue in general.
I'm 99% positive that the bug will be fixed once this is applied.