1093325: Prevent rhsm-debug from throwing tbs

rhsm-debug was not catching all exceptions at the
top level. This is normally okay for really unexpected
exceptions, but rhsm-debug can end up getting invoked
in the process of abrt handling top level exceptions. Or
from running 'sosreport'. Since there isn't much we
can do about these exceptions, catch them all and
warn to stderr.
Merge pull request #1051 from candlepin/alikins/1093325_rhsmdebug_catchall

1093325: Prevent rhsm-debug from throwing tbs