Merge lp://qastaging/~kwmonroe/charms/trusty/layer-ibm-im/switch-to-resources into lp://qastaging/~ibmcharmers/charms/trusty/layer-ibm-im/trunk

update fixpack placeholder description

update tests since we can test charm deployment with a placeholder resource

be more explicity with log/status messages

never let the grep fail when detecting an empty fixpack (set -e will make the hook fail on subshell failures); make check-fixpack only run during upgrade-charm (otherwise it ran on update-status, every 5 minutes)

use underscores instead of hyphens in function names

fixup last commit (missed an extra ibm_im_fp_empty assignment)

update sentry message for placeholder resource test

tweak sentry status message in amulet test

change upgrade-charm hook logic

The first time a fixpack resource was uploaded, the upgrade-charm hook would
fetch it, md5sum it, and compare that sum to a bogus previous value (because
there was no previous valid fixpack). This sum mismatch triggered the install
of a new fixpack, which goes out to re-fetch it. The double-fetch on initial
fixpack (first in upgrade-charm, then in install_ibm_im_fixpack) is
inefficient.

Instead, upgrade-charm now checks for the ibm-im.updated state, which is only
set when a fixpack gets installed. On initial fixpack upload, this state will
not be set, so we avoid the double fetch.