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Four words and I had a typo.  Sheesh.
Clear the variable in case we jump to err.
Support new configuration options added by the applications, using a new
method, WT_CONNECTION::configure_method.

For some reason I can'quite figure out, this set of changes made lint run a
bunch better on some sources, and showed up a few different uninitialized
variables in error paths.  Got me why, but they're real, and I fixed them.
I changed an error message, update the test suite to match.