Item12980: Fix shebang in git hooks.

MichaelDaum points out /usr/bin/env perl   is kinder to perlbrew & plenv
environments.

git-svn-id: http://svn.foswiki.org/branches/Release01x01/core@17862 0b4bb1d4-4e5a-0410-9cc4-b2b747904278