Instead, run things out of $PATH.
Fixes errors like these (on NixOS):
munin-available-plugins/.mysql_slowqueries-wrapped: line 67: /usr/bin/printf: No such file or directory
(Basically, this unbreaks some plugins.)
* Add needed dependencies:
coreutils, python, ruby, java and several Perl modules (Time::HiRes
1.9.724 is no longer available, bump to 1.9725)
* Use sha256 instead of md5 (more secure)
* Wrap munin perl scripts so they find their dependencies at runtime
* Rework meta description attributes.
FIXME/TODO: munin is still not usable; it tries to write log files and
web graphs to its installation path.
