CHARM_DIR not set in command: subprocess

[cmars]

Needs verification.

[simonklb]

I took a quick look at this and I think this is actually charmhelpers that is a bit out of date. By the look of it CHARM_DIR is an out-dated variable name while JUJU_CHARM_DIR is the one to use - which is also the one included in the collect-metrics hook.

[simonklb]

Oh and layer-basic as well it seems. I wonder if the JUJU_CHARM_DIR simply wasn't ever adopted since it was added over two years ago.