Using a stale obj from Tcl_GetResultObj() to store error results

caused incorrect data in result array and possibly segmentation
violations when searches terminated due to errors such as timeout,
exceeding search limit, or the remote server going down in the middle
of a search.  Also correctly puts error message on top of
traceback stack (instead of randomly in memory per the stale result obj).

A segmentation violation could have manifested later in the program's
life, or perhaps during termination of the interpreter.