This CR cleans up the panic messages when unsupported capabilities
are detected. The messages were seemingly written to include simply
the channel ID instead of the entire ConfigtxValidator() object.
This CR also cleans up a few other error messages and a linter problem.

Change-Id: I337dc6cdecc7c4ab897e414530798e5659bf85e5
Signed-off-by: Will Lahti <wtlahti@us.ibm.com>