Since breaking the filename construction out to a helper function,
Hydra::Model::DB is no longer used. Importing Hydra::Helper::Nix,
however, has the potential to break tests, so just use the functions we
need without importing the entire module.
run3 just seems to do better handling for what we want to do, and
requires less deep-reaching changes to this plugin to get it to play
nice, as IPC::Run::run would.
This uses the somewhat restrictive umask of 0027 so that people outside
the user or group cannot read the files. This also helps to inhibit
TOCTOU where someone else has a handle to our file before we chmod it
and after we close it.
Plugins are now disabled at startup time unless there is some relevant
configuration in hydra.conf. This avoids hydra-notify having to do a
lot of redundant work (a lot of plugins did a lot of database queries
*before* deciding they were disabled).
Note: BitBucketStatus users will need to add 'enable_bitbucket_status
= 1' to hydra.conf.