Removed d6cage reload module warning messages

Previously, d6cage would log errors when the same module
was loaded more than once.

It is unclear whether this behavior is useful, and it
produced many errors during testing.  This change
logs a warning instead of an error when a module
is reloaded.

Closes-bug: 1360443
Change-Id: Id1add83b2fa8b7432ac5cc5d3156a13af92ba858
Merge "Removed d6cage reload module warning messages"