We no longer check for the log file here, fix a comment.
Fix a comment, __session_close_cache is not called holding the schema
lock.
The connection handle code shouldn't really be dealing with session-style
cached handles (WT_DATA_HANDLE_CACHE), and there's duplicated code to close
all of the cached session handles. Instead of exporting a call to discard
a single handle, export a call to discard all of the handles.
Skip decrementing the connection's reference count when discarding
session-cached handles for internal sessions.