Return an error when the configuration merge fails.
Fix the separator character error message to complain about the correct key.
Don't use '.' as a key name nested structure separator character during
configuration merge, applications can create their own nested key name
space by specifying a shared library name to the "extensions" configuration
string, and '.' is extremely likely to appear in that shared library name.
Reference #1229.
Typo, returning 0, not "ret", don't lose the return value on failure.
Typo, calling log_print_err() with the wrong return error value.
Typo, verify_checkpoint wasn't returning the final error status.
Typo, final return value was being lost on failure.
Add a check for a return(0) after an error lable.
Fix a salvage bug: if salvaging a variable-length column-store page, and
we split a key range inside an RLE unit, we can end up with multiple key
range chunks referencing a single overflow value when during the leaf-page
merge phase.  There's not much we can do at that point, delete the value.
Reference #1222.